Chapter 6 - Systems of Equations and Inequalities - Common Core Cumulative Standards Review - Selected Response - Page 413: 3

$C$

First, we use distribution on the left side of the equation: $12x + 12 = 36$ Subtract $12$ from both sides of the equation to collect constant terms on the right side of the equation: $12x = 24$ Divide each side of the equation by $12$ to solve for $x$: $x = 2$ The answer is option $C$.