Chapter 4 - Writing Linear Functions - 4.1 - Writing Equations in Slope-Intercept Form - Exercises - Page 180: 38

$x=28$

The given equation is $3(x-15)=x+11$ This can be written as $3x-45=x+11$ Add 45 to both sides of the equation. Then, $3x-45+45=x+11+45$ Or $3x=x+56$ Subtract $x$ from both sides of the equation to get $2x=56$ Now, divide both sides of the equation by $2$. Then, $x=28$.