Step-by-step explanation:
f(x) = 3x² + 4x
f(g) = √( x + 7)
1)
If x = -5, f(-5) = 3(-5)² + 4(-5)
3(25) + 4(-5)
75-20
55
Not sure how they get 95 though. I think they forgot it was a negative instead of a positive.
2)
If x = -3, f(-3) = 3(-3)² + 4 (-3)
3(9) - 12
27 - 12
15
3)
If x = 9, g(9) = √(9 + 7)
√(16) = 4
4) If g(x) = 0, then
0 = √(x + 7)
0 = x + 7
x = -7
