Question

Solve the system of equations below.

-3x + 6y = 9

5x + 7y = -49

Answer 1

`x=-7`

`y=-2`

Explanation:

Given system of equations,

-3x + 6y = 9 ------(1)

5x + 7y = -49 ------(2),

LCM (3, 5) = 15,

5 × equation (1) + 3 × equation (2),

We get,

30y + 21y = 45 - 147

51y = -102

`\implies y=-2`

From equation (1),

`-3x+6(-2)=9`

`-3x-12=9`

`-3x=9+12`

`-3x=21`

`x=-7`