SAT Simultaneous Equation

SAT Simultaneous Equation

Part 1: Introduction to Simultaneous Equations

At MKSprep, our comprehensive SAT prep courses delve into a variety of subjects to help you build the knowledge base you’ll need to excel on your exam. Today, we’re focusing on a key area of mathematics that’s often tested on the SAT: simultaneous equations.

What are simultaneous equations, you ask? Let’s start with the basics.

Simultaneous equations are a set of equations containing multiple variables that are solved simultaneously, hence the term ‘simultaneous.’ The objective is to find the values of the variables that satisfy all the equations in the set at once.

These equations can seem challenging at first glance. However, understanding simultaneous equations can significantly boost your mathematical prowess and, by extension, your SAT score. They also have widespread application in various fields, including physics, engineering, and economics.

At MKSprep, located in the heart of Nepal, we aim to break down complex topics like this into manageable chunks. Through a blend of theory and practical examples, we ensure students grasp the concept firmly.

In this course, we will cover:

  1. The Basics of Simultaneous Equations: Understand what simultaneous equations are, their importance, and their real-life applications.
  2. Methods of Solving Simultaneous Equations: Learn the different techniques to solve these equations, such as substitution, elimination, and graphical methods.
  3. Problems involving Simultaneous Equations: Engage with a variety of problems to put the theory into practice. We provide detailed solutions and step-by-step guides to help you understand the process.
  4. Simultaneous Equations and the SAT: Explore the types of SAT questions that involve simultaneous equations and get expert tips on how to tackle them effectively.
  5. Practice with Simultaneous Equations: Get ample practice with a variety of questions to strengthen your grasp of simultaneous equations.
  6. Quadratic Simultaneous Equations: Understand how simultaneous equations can involve quadratic equations and learn the methods to solve them.
  7. Advanced Applications of Simultaneous Equations: Look into more complex applications and problems involving simultaneous equations.
  8. Review and Test: Review everything you’ve learned about simultaneous equations and test your knowledge with an SAT-style practice test.

Stay with us as we dive deeper into the world of simultaneous equations, and remember—every mathematical problem is an opportunity to learn and grow. At MKSprep, we’re committed to helping you turn these opportunities into a higher SAT score. Let’s get started!

[Next: The Basics of Simultaneous Equations]

Part 2: The Basics of Simultaneous Equations

In the previous section, we introduced the concept of simultaneous equations. Today, we’ll delve deeper into understanding their fundamentals. As we navigate through the basics, remember that every concept learned here at MKSprep is a step closer to excelling at the SAT.

What Are Simultaneous Equations?

Simultaneous equations are a set of two or more equations with the same variables. They are called ‘simultaneous’ because all equations in the set must be true at the same time.

Here is an example of a simple system of simultaneous equations:

x + y = 7

2x – y = 3

In this system, one solution (x, y) satisfies both equations.

The Purpose of Simultaneous Equations

Why do we need simultaneous equations? In many real-life situations, we have more than one unknown and need more than one piece of information (equation) to find the unknowns.

For instance, imagine you are buying apples and oranges from a fruit market. If you know the total number of fruits and the total cost but don’t know the individual prices, you can create a system of simultaneous equations to solve for both the price of an apple and an orange.

Types of Simultaneous Equations

There are primarily two types of simultaneous equations:

  1. Linear Simultaneous Equations: Both equations are linear, meaning the highest power of the variables is one.
  2. Non-linear Simultaneous Equations: At least one of the equations is non-linear, meaning at least one equation has a variable with a power of two or more.

The kind of simultaneous equations you’ll deal with most often on the SAT are linear simultaneous equations.

In our next module, we will discuss the methods used to solve these equations, giving you the tools you need to tackle a key part of the SAT math section. Stay tuned for an exciting journey ahead.

[Next: Methods of Solving Simultaneous Equations]

Part 3: Methods of Solving Simultaneous Equations

Now that we understand the basics of simultaneous equations let’s move on to the core of this topic: the methods for solving these equations. At MKSprep, we believe in taking a comprehensive approach to learning, so we’ll discuss three main methods: substitution, elimination, and graphical.

Substitution Method

In the substitution method, we rearrange one of the equations to make one variable subject of the formula (i.e., express one variable in terms of the other variable). We then substitute this into the other equation. This method is especially useful when one equation is already in a form that makes substitution easy.

For example, consider the following system of equations:

x + y = 10

x = y + 2

From the second equation, we can see that x is already expressed in terms of y. We can substitute x = y + 2 into the first equation to solve for y, then substitute y back into the second equation to find x.

Elimination Method

The elimination method involves adding or subtracting the equations in order to eliminate one of the variables, making it possible to solve for the other variable. This method is especially effective when the coefficients of one of the variables in both equations are equal or easily made equal.

For example, consider the following system of equations:

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3x + 2y = 8

3x – y = 1

In this case, we can subtract the second equation from the first to eliminate x and solve for y. We can then substitute y into one of the original equations to solve for x.

Graphical Method

The graphical method involves plotting the equations on a graph and finding the point(s) where they intersect. This method can be more time-consuming and less precise, but it is a good way to visualize the solution.

For example, the simultaneous equations y = 2x + 1 and y = -x + 3 are lines that intersect at a single point on a graph. The coordinates of that point (x, y) are the solution to the simultaneous equations.

It’s important to note that the SAT is unlikely to require you to use the graphical method, as it requires graph paper and more time than is typically available for each question. However, understanding this method can help reinforce your understanding of simultaneous equations and how their solutions work.

In the next section, we’ll take these methods and apply them to a variety of problems, helping you cement your understanding of simultaneous equations. Remember, at MKSprep, we’re here to guide you every step of the way on your journey to SAT success.

[Next: Problems involving Simultaneous Equations]

Part 4: Problems Involving Simultaneous Equations

Mastering the theory of simultaneous equations is one thing, but applying it to actual problems is where the real learning happens. At MKSprep, we strongly believe in the power of practical examples to enhance understanding. Let’s take the methods we’ve learned and apply them to some SAT-style problems.

Problem 1: Substitution Method

Let’s start with a problem that’s best solved using the substitution method.


1) 2x + 3y = 22

2) x = y + 4

To solve this, we first substitute equation (2) into equation (1), then solve for y.

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2(y + 4) + 3y = 22

2y + 8 + 3y = 22

5y + 8 = 22

5y = 14

y = 14 / 5

y = 2.8

Substitute y = 2.8 into equation (2) to find x.

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x = 2.8 + 4

x = 6.8

So the solution is (6.8, 2.8).

Problem 2: Elimination Method

Next, let’s look at a problem that’s a good candidate for the elimination method.

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1) 5x – 2y = 18

2) 3x + 2y = 10

By adding equation (1) and equation (2), the y-variable cancels out, and we’re left with an equation we can solve for x.

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5x – 2y + 3x + 2y = 18 + 10

8x = 28

x = 28 / 8

x = 3.5

Substitute x = 3.5 into equation (1) to find y.

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5(3.5) – 2y = 18

17.5 – 2y = 18

-2y = 0.5

y = 0.5 / -2

y = -0.25

So the solution is (3.5, -0.25).

These problems give you a good idea of how to apply the methods we’ve learned to solve simultaneous equations. In the next module, we’ll explore how these concepts are tested on the SAT and give you some expert tips for tackling these questions effectively.

[Next: Simultaneous Equations and the SAT]

Part 5: Simultaneous Equations and the SAT

Welcome back to our SAT prep course at MKSprep. Now that we’ve covered the basics of simultaneous equations and practiced solving them let’s focus on how these questions might appear on the SAT and how best to approach them.

The SAT often presents simultaneous equations problems in word problem format, testing your ability to translate real-life situations into mathematical terms. Here, we will break down the process and give you some expert tips on how to tackle these effectively.

Understand the Problem

When faced with a word problem, take your time to read through and understand the situation being described. Identify the unknowns (which will become your variables) and the relationships between them (which will become your equations).

For example, let’s consider the following SAT-style question:

“John has $1.50 in quarters and dimes. He has a total of 10 coins. How many quarters and dimes does John have?”

Here, we have two unknowns – the number of quarters (q) and the number of dimes (d). We can create two equations based on the information given:

  1. q + d = 10 (from the total number of coins)
  2. 0.25q + 0.10d = 1.50 (from the total value of the coins)

Choose the Best Method

As we learned earlier, the substitution method is often easier to use when one variable is isolated, and the elimination method is effective when one variable’s coefficients are equal or can be easily made equal.

The substitution method would be a good choice in the equations above since equation 1 is already solved for q + d.

Solve the Equations

Solving our problem:

Subtracting the second equation from the first (remember that 1 quarter = 2.5 dimes), we have:

1.5d = 7.5, which gives d = 5.

Substituting d = 5 into the first equation gives us q = 5.

So, John has 5 quarters and 5 dimes.

Check Your Solution

Always take a moment to check if your solution makes sense in the context of the original problem. Here, we have found that John has 5 quarters and 5 dimes, which indeed adds up to 10 coins and $1.50.

Remember, understanding simultaneous equations can significantly boost your SAT score. In our next session, we will explore more practice problems to enhance your skills. Practice is the key to perfection!

[Next: Practice with Simultaneous Equations]

Part 6: Practice with Simultaneous Equations

Welcome back to our SAT prep course at MKSprep! In this section, we’re going to provide you with additional practice problems to cement your understanding of simultaneous equations further. After all, practice makes perfect!

We’ve discussed the basics, methodologies, and SAT-specific strategies surrounding simultaneous equations. Now it’s time for you to apply that knowledge. Here are some practice problems for you to work through.

Practice Problem 1

Maria and Juan are saving money. Maria saves $10 a week, while Juan saves $15 a week. After several weeks, Maria has saved $80 more than Juan. How many weeks have they each been saving?

Hint: Set up two equations, one for Maria’s savings and one for Juan’s savings.

Practice Problem 2

Two trains depart from the same station at the same time, traveling in opposite directions. One train travels at a speed of 60 mph, while the other train travels at a speed of 80 mph. After how many hours will they be 420 miles apart?

Hint: Remember that distance = speed * time.

Practice Problem 3

The sum of two numbers is 15, and their difference is 3. What are the numbers?

Hint: Try using the substitution method to solve this problem.

Once you’ve worked through these problems, you can check your solutions. Don’t be discouraged if you don’t get them all right on the first try. Practice is about learning from mistakes and improving your understanding.


  1. Maria and Juan have each been saving for 12 weeks.
  2. The trains will be 420 miles apart after 3 hours.
  3. The numbers are 9 and 6.

Keep practicing, and you’ll continue to improve. Next up, we’ll take our understanding of simultaneous equations to the next level by exploring quadratic simultaneous equations. Stay tuned!

[Next: Quadratic Simultaneous Equations]

Part 7: Quadratic Simultaneous Equations

We’ve extensively covered linear simultaneous equations in our SAT prep course at MKSprep. Today, we’re going to broaden our horizons and explore quadratic simultaneous equations.

While these equations are less likely to appear on the SAT than their linear counterparts, they still come up occasionally, and understanding them can deepen your overall comprehension of algebra.

What are Quadratic Simultaneous Equations?

Quadratic simultaneous equations are sets of equations with at least one quadratic equation. A quadratic equation is an equation of the second degree, meaning it contains at least one term that is squared. The standard form is ax² + bx + c = 0.

For example:

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y = x² + 3x + 2

y = 2x + 1

How to Solve Quadratic Simultaneous Equations

The process for solving quadratic simultaneous equations is similar to that of linear ones, with a twist. You can still use the substitution or elimination methods. Here’s a brief overview using the substitution method:

  1. Isolate a variable in the linear equation. In the example above, the second equation is already solved for y.
  2. Substitute the expression from the linear equation into the quadratic equation. In our example, this means replacing y in the first equation with 2x + 1:

2x + 1 = x² + 3x + 2

  1. Simplify and solve the resulting quadratic equation. This usually involves moving all terms to one side of the equation and factoring or using the quadratic formula. In our example:

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0 = x² + x – 1

Solving this equation gives x = 0.618 and x = -1.618.

  1. Substitute the solutions for x into the linear equation to find the corresponding y-values. In our example:

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When x = 0.618, y = 2(0.618) + 1 = 2.236

When x = -1.618, y = 2(-1.618) + 1 = -2.236

So the solutions to the system of equations are (0.618, 2.236) and (-1.618, -2.236).

Understanding and solving quadratic simultaneous equations might be a challenge at first, but it’s a crucial skill that can come in handy in the more complex math questions on the SAT. Our final section’ll discuss simultaneous equations with more practice problems, this time involving quadratics.

[Next: Practice with Quadratic Simultaneous Equations]

Part 8: Practice with Quadratic Simultaneous Equations

Welcome to the final module of our simultaneous equations topic in our SAT prep course at MKSprep! In this segment, we’ll provide you with some practice problems involving quadratic simultaneous equations. Practice is the key to mastering this challenging yet rewarding topic.

Remember, while quadratic simultaneous equations are less common on the SAT, being prepared for them gives you an edge. Let’s dive into some practice problems!

Practice Problem 1

Solve the following simultaneous equations:

  1. y = x² + 3x + 2
  2. y = 2x + 1

Hint: You can use the substitution method to solve this problem.

Practice Problem 2

Solve the following simultaneous equations:

  1. y = x² – 5x + 6
  2. y = 3x – 2

Hint: Again, the substitution method will be useful.

Practice Problem 3

Solve the following simultaneous equations:

  1. y = x² + 4x + 4
  2. y = x + 2

Consider what it means when a quadratic equation equals a straight line.

Now, take some time to solve these problems. Don’t rush; these equations are more complex than the linear ones we’ve previously discussed. Once you’re done, you can check your solutions:


  1. The solutions are (-1, -1) and (-2, -3).
  2. The solutions are (1, 1) and (2, 4).
  3. The solution is (-2, 0).

Remember, it’s not just about getting the right answer but understanding the process to get there. Reflect on any mistakes you made and what you can learn from them. Quadratic simultaneous equations can be challenging, but they’ll become another tool in your mathematical toolbox with practice.

Thank you for being a part of this journey through simultaneous equations! As always, MKSprep is here to support you in your SAT preparation. Stay tuned for our next module to explore a new topic to help you achieve your SAT goals.