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Justine asked her group members to do this calculation: Pick a number, multiply by 5 , and subtract 2 . Quentin got 33 for an answer. Explain how Justine could determine what number Quentin picked. What number did Quentin pick?

Short Answer

Expert verified
Quentin picked the number 7.

Step by step solution

01

Understanding the Equation

First, we need to understand the equation given in the problem. If Quentin picked a number, let's call it \( x \). According to the problem, Quentin's process involves multiplying \( x \) by 5 and then subtracting 2. His result is 33. We can express this as an equation: \( 5x - 2 = 33 \).
02

Isolate the Term with the Variable

To find \( x \), we need to isolate it on one side of the equation. We start by adding 2 to both sides of the equation to eliminate the \( -2 \) on the left side: \[ 5x - 2 + 2 = 33 + 2 \]. This simplifies to \( 5x = 35 \).
03

Solve for the Variable

Now that we have \( 5x = 35 \), we solve for \( x \) by dividing both sides by 5: \[ \frac{5x}{5} = \frac{35}{5} \]. This gives \( x = 7 \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Problem-Solving
Let's dive into the world of problem-solving and uncover how to approach challenges like the one Justine presented to her group. Problem-solving in mathematics is all about finding a path from the given information to the desired solution. This involves identifying what you know, what you need to find out, and the steps necessary to transition from one to the other. In Justine's scenario, we start with the operations that transform a number into the final outcome Quentin received.

Firstly, we decode the problem by understanding the sequence of operations: multiplying by 5 and subtracting 2. The key to problem-solving is breaking down these operations into smaller, manageable parts. We then express these steps in the form of an algebraic equation, which is essentially a mathematical sentence that illustrates the relationship between numbers and operations.

Once we set up the equation properly, solving it becomes a systematic process. Each step should bring us closer to identifying the mystery number that Quentin originally picked. Remember, problem-solving is not only about finding an answer but understanding the rationale behind each phase of the solving process.
Linear Equations
Linear equations are equations of the first degree, meaning they involve variables with an exponent of 1. They take the form \( ax + b = c \), where \( a \), \( b \), and \( c \) are constants. In Justine's example, we are dealing with a simple linear equation: \( 5x - 2 = 33 \).

The beauty of linear equations lies in their straightforward nature. Each equation has one variable, typically represented by \( x \), which we aim to find. Solving linear equations requires a few systematic steps:
  • Start by simplifying both sides of the equation. This can include removing any constants by adding or subtracting them.
  • Then, isolate the variable by performing inverse operations to get \( x \) alone on one side of the equation.
  • Finally, solve for \( x \) by performing any remaining arithmetic operations, such as division or multiplication.


In our original equation, \( x \) represents the number Quentin picked, and through isolating and solving the equation, we discover that \( x = 7 \). Linear equations are fundamental in algebra, providing the building blocks for more complex math topics.
Variables
Variables play a crucial role in algebra and help us generalize and solve problems involving unknown numbers. A variable is typically a letter used to represent an unknown quantity in an equation or a mathematical expression. In Quentin's problem, the variable \( x \) stands for the number he chose initially.

Understanding how variables function within equations is essential for solving them. They allow us to write equations that model real-world scenarios and make sense of unknowns. Essentially, variables act as placeholders that can be manipulated to find the value they represent.

The manipulation of variables involves using algebraic techniques to uncover the unknown value. For instance, in the equation \( 5x - 2 = 33 \), \( x \) must be isolated through arithmetic operations to determine its value. This involves applying inverse operations, such as adding or subtracting constants and dividing or multiplying by coefficients.
  • Ensure you perform operations on both sides of the equation to maintain equality.
  • The goal is to transform the equation to expose the variable's value clearly.


Eventually, the variable that once caused uncertainty becomes known, revealing the mystery number Quentin selected.

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