# How do you solve the following linear system:  y = - 3x + 8, 2x + y = 15 ?

Nov 14, 2015

$x = - 7$
$y = 29$

#### Explanation:

$y = - 3 x + 8$ --------------------(1)
$2 x + y = 15$ ---------------------(2)

Substitute >$y = - 3 x + 8$ in equation (2)

$2 x + \left(- 3 x + 8\right) = 15$
$2 x - 3 x + 8 = 15$
$- x = 15 - 8 = 7$
$x = - 7$

Put $x = - 7$ in equation (1)

$y = - 3 \left(- 7\right) + 8$
$y = 21 + 8 = 29$
$y = 29$