Answer:
The correct answer is 6.
Step-by-step explanation:
To find this, first find f(-3)
f(x) = -3x + 9
f(-3) = -3(-3) + 9
f(-3) = 9 + 9
f(-3) = 18
Now we do the same for f(7)
f(x) = -3x + 9
f(7) = -3(7) + 9
f(7) = -21 + 9
f(7) = -12
Now we add them together
18 + -12 = 6
