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

To solve 2x + y = 15 (-$\frac{1}{2}$x + y = 5 )$\times$ -1 2x + y = 15 $\frac{1}{2}$x -y = -5 --> add the two equations 2x + $\frac{1}{2}$x = 15-5 $\frac{5}{2}$x = 10 5x = 10(2) 5x =20 x=4 To solve for y 2(4)+y =15 8 + y = 15 y = 15-8 y = 7