# How do you solve the system y=3-4x and -3x-y=2?

Jun 3, 2015

y=color(red)(3-4x ....equation $\left(1\right)$
$- 3 x - y = 2$.......equation $\left(2\right)$

substituting equation $\left(1\right)$ in equation $\left(2\right)$

$- 3 x - y = 2$
$- 3 x - \textcolor{red}{\left(3 - 4 x\right)} = 2$
$- 3 x \textcolor{red}{- 3 + 4 x} = 2$
x=2 + 3, color(blue)(x = 5

substituting $x$ in equation $\left(1\right)$ to find $y$
$y = 3 - 4 x$
y=3-20 , color(blue)(y = -17

the solutions are : color(blue)( x = 5 , y = -17