# How do you solve the system of equations: 3x - y = 8, y = x - 4?

Aug 15, 2015

The solutions are
color(blue)(x=2,y=-2

#### Explanation:

$3 x - y = 8$........equation $1$
 y =color(blue)( x - 4..........equation $2$

Solving by substitution .

Substituting equation $2$ in equation $1$
$3 x - \left(\textcolor{b l u e}{x - 4}\right) = 8$

$3 x - \textcolor{b l u e}{x + 4} = 8$
$2 x + 4 = 8$
$2 x = 4$
color(blue)(x = 2

Finding $y$ by substituting $x$ in equation $2$
$y = x - 4$
$y = 2 - 4$
color(blue)(y=-2