Chapter 8 - Section 8.1 - Systems of Linear Equations: Substitution and Elimination - 8.1 Assess Your Understanding - Page 555: 40

$x=\frac{1}{2}$ $y=2$

$2x-y=-1$ $(1)$ $x+\frac{1}{2}y=\frac{3}{2}$ $(2)$ Multiply Eq $(2)$ by 2 $2x-y=-1$ $(1)$ $2x+y=3$ $(2)$ Add the two equations together $(2x+2x) + (-y+y) = -1 + 3$ $4x=2$ $x=\frac{1}{2}$ Substitute into Eq $(1)$ $y=2x+1$ $y=2 \times \frac{1}{2}+1$ $y=2$