f(x)=x^3+4 f=1, f=-1

Are the answer to this 5 and 3
I must not understand

1 answer

f(x)=x^3+4

f=1
f(1)=(1)^3+4
(1)^3=1 because 1X1X1=1
1+4=5
so f(1)=5

f=-1
f(-0)=(-1)^3+4
(-1)^3=-1
because -1x-1x-1=1x-1=-1
-1+4=3
so f(-1)=3