## Algebra 1: Common Core (15th Edition)

We first add 15 to both sides to get that x/2 + x/3 =15. We need a common denominator (bottom of the fraction) to add the numerators (tops of the fractions). Thus, we multiply $\frac{x}{3}$ by $\frac{2}{2}$ to get $\frac{2x}{6}$, and we multiply $\frac{x}{2}$ by $\frac{3}{3}$ to get $\frac{3x}{6}$. We add the two fractions to get that $\frac{5x}{6}=15$. We multiply both sides by 6 to get that 5x=90. We finally divide both sides by 5 to get that x=18.