Question

$9x + 12 - 3x = 72$

Explanation:

Step1: Combine like terms

$9x - 3x + 12 = 72$
$6x + 12 = 72$

Step2: Subtract 12 from both sides

$6x + 12 - 12 = 72 - 12$
$6x = 60$

Step3: Divide by 6 on both sides

$\frac{6x}{6} = \frac{60}{6}$
$x = 10$

Answer:

$x = 10$