# How do you solve 2x + y = -1 and x - 2y = 7?

Aug 17, 2015

x = 1 ; y = - 3

#### Explanation:

2x + y= −1 ___(1)
x − 2y = 7
____(2) $\times$ 2
2x - 4y = 14 ------------------------(3)

Subtract (3) from (1)

2x + y= −1
2x - 4y = 14

$$  5y = - 15


$$    y = -3


Substitute y = - 3 in equation (1)

2x + ( - 3) = - 1

2x - 3 = - 1 Multiply both sides by 5
10x - 15 = - 5
10x = - 5 + 15 = 10
x = $\frac{10}{10}$ = 1
x = 1