## Precalculus (10th Edition)

$x=50$
Add 15x to both sides: $60x-900+15x=-15x+2850+15x \\75x-900=2850$ Add 900 to both sides: $75x-900+900=2850+900 \\75x=3750$ . Divide both sides by 75: $\frac{75x}{75}=\frac{3750}{75} \\x=50$.