x = - 2
y = 5
Hi there !
2x + 9 = y
y = - 4x - 3
equality
2x + 9 = - 4x - 3
2x + 4x = - 9 - 3
6x = - 12
x = - 12 : 6
replace x = - 2
2(-2) + 9 = y
- 4 + 9 = y
Good luck !