Solve the system.
3x^2+4x-y=8
y+3=2x^2+4x
organize things a bit better
y = 3x^2+4x-8
y = 2x^2+4x-3
so,
3x^2+4x-8 = 2x^2+4x-3
x^2-5 = 0
x = ±√5
now use that to find y.
3x^2+4x-y=8
y+3=2x^2+4x
y = 3x^2+4x-8
y = 2x^2+4x-3
so,
3x^2+4x-8 = 2x^2+4x-3
x^2-5 = 0
x = ±√5
now use that to find y.