# How do you solve by substitution x - 2y = -1 and 2x - y = 4?

Jun 10, 2015

The solution for the system of equations is
 color(blue)(x = 3 , y =2

#### Explanation:

$x - 2 y = - 1$
x =color(blue)( -1+2y........equation $\left(1\right)$

$2 x - y = 4$............equation $\left(2\right)$

Substituting equation $1$ in $2$ to find $y$
$2 \textcolor{b l u e}{\left(- 1 + 2 y\right)} - y = 4$
$- 2 + 4 y - y = 4$
$3 y = 6$
 color(blue)(y=2

Substituting $y$ in equation $1$ to find $x$:
$x = - 1 + 2 y$
$x = - 1 + 4$
 color(blue)(x = 3