Question

Hi how do I solve this simultaneous equation

Answer 1

Answer:

M (-3, -5/2)

N (3, -1)

Step-by-step explanation:

Solve the first equation for x.

4y = x − 7

x = 4y + 7

Substitute into the second equation.

x² + xy = 4 + 2y²

(4y + 7)² + (4y + 7)y = 4 + 2y²

Simplify.

16y² + 56y + 49 + 4y² + 7y = 4 + 2y²

18y² + 63y + 45 = 0

2y² + 7y + 5 = 0

Factor.

(y + 1) (2y + 5) = 0

y = -1 or -5/2

Plug back into the first equation to find x.

x = 4(-1) + 7 = 3

x = 4(-5/2) + 7 = -3

M (-3, -5/2)

N (3, -1)