Answer:
(x, y) = (- 3, - 6)
Step-by-step explanation:
given the 2 equations
- 4x + y = 6 → (1)
- 5x - y = 21 → (2)
rearrange equation (1) expressing y in terms of x
y = 6 + 4x → (3)
Substitute y = 6 + 4x into equation (2)
- 5x - (6 + 4x) = 21
- 5x - 6 - 4x = 21
- 9x - 6 = 21 ( add 6 to both sides )
- 9x = 27 ( divide both sides by - 9 )
x = - 3
Substitute x = - 3 into (3)
y = 6 - 12 = - 6
solution is (- 3, - 6)