Answer:
f(9) = - 59
Step-by-step explanation:
Substitute x = 9 into f(x) , that is
f(9) = - (9)² + 9 + 13
= - 81 + 22
= - 59
-59
f(x) =-x^2+x+13
Let x = 9
f(9) = - (9)^2 +9+13
= -81 +9+13
= -59
