Question

Solve the following system of equations:

xy = -4
2y = x- 6
Answer choices:
A. (-1, 4), (-2, 2)
B. (2,-2), (4, -1)
C. (4,3), (-3,-4)
D. (-4, 12).(-1, -3)

Answer 1

`xy = 4 \\ 2y = x - 6 \\ \\ xy = 4 \\ x = 6 + 2y`

`(6 + 2y)y = - 4 \\ {y}^(2) + 3y + 2 = 0 \\ d = {3}^(2) - 4 * 2 = 9 - 8 = 1 = {1}^(2)`

`y = ( - 3 + 1)/(2) = - 1 \\ \\ y = ( - 3 - 1)/(2) = - 2`

`- 2x = - 4 \\ x = 2 \\ \\ - x = - 4 \\ x = 4`

Answer: B) (2; -2), (4; -1)