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Solve: 15 + x = 3x - 17

Question:

Solve: 15 + x = 3x - 17

Evaluate

The term evaluate may seem daunting but it simply means doing what the mathematical operations say. An algebraic expression is a set of instructions that has set rules, follow the rules and you might be pleasantly surprised with the results how simple it it.

Answer and Explanation:

Given the equation:

{eq}15 + x = 3x - 17 {/eq}

We will solve for the value of {eq}x {/eq} by collecting like terms:

{eq}15 + 17 = 3x -x {/eq}

{eq}32 = 2x {/eq}

Dividing both sides by 2:

{eq}\displaystyle \frac{32}{2} = \frac{2x}{2} {/eq}

{eq}16 = x {/eq}

To check we substitute the value in the equation:

{eq}15 + x \stackrel{?}{=} 3x-17 \ for \ x=16 {/eq}

{eq}15 + 16 \stackrel{?}{=} 3(16) -17 {/eq}

{eq}31 \stackrel{?}{=} 48 -17 {/eq}

{eq}31 \stackrel{\checkmark}{=} 31 {/eq}

This means that the value of {eq}x {/eq} in {eq}15 + x = 3x - 17 {/eq} is {eq}16 {/eq}.


Learn more about this topic:

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Evaluating Simple Algebraic Expressions

from ELM: CSU Math Study Guide

Chapter 6 / Lesson 3
75K

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