Chapter 1: Q26 (page 10)

Find the value of the variable.
$12 = 3 r - 9$

Short Answer

Expert verified

The value of the variable is $r = 7$ .

Step by step solution

Step 1. Add 9.

To find the value of variable r in the equation $12 = 3 r - 9$ , add 9 on both sides of the equation.

$12 + (9) = 3 r - 9 + (9)$

Step 2. Simplify the equation.

To simplify, remove all the brackets and combine the like terms.

$\begin{array}{l} 12 + 9 = 3 r - 9 + (9) \\ 21 = 3 r \end{array}$

Step 3. Divide by 3.

To find the value of variable r in the equation $21 = 3 r$ , divide both sides of the equation by 3.

$\frac{21}{3} = \frac{3 r}{3}$

Step 4. Simplify the equation.

To further simplify, cancel the common factors of 3 on both sides.

$\begin{array}{l} \frac{3 \times 7}{3} = \frac{3 r}{3} \\ 7 = r \end{array}$

Step 5. Verify the value.

In order to verify the value of r, substitute 7 for r into the equation $12 = 3 r - 9$ .

$\begin{array}{l} 12 = 3 \times 7 - 9 \\ 12 = 21 - 9 \\ 12 = 12 True \end{array}$

Hence, the value of the variable is $r = 7$ .

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Find the value of the variable.
$12 = 3 r - 9$

Short Answer

Step by step solution

Step 1. Add 9.

Step 2. Simplify the equation.

Step 3. Divide by 3.

Step 4. Simplify the equation.

Step 5. Verify the value.

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Find the value of the variable.12=3r−9

Short Answer

Step by step solution

Step 1. Add 9.

Step 2. Simplify the equation.

Step 3. Divide by 3.

Step 4. Simplify the equation.

Step 5. Verify the value.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Decision Maths

Logic and Functions

Discrete Mathematics

Probability and Statistics

Geometry

Theoretical and Mathematical Physics

Study anywhere. Anytime. Across all devices.

Find the value of the variable.
$12 = 3 r - 9$