Question

Given that

f
(
x
)
=
x
2
+
7
x
and
g
(
x
)
=
x
+
7
, calculate
(a)
(
f
∘
g
)
(
−
5
)

Answer 1

18

Explanation:

We want to find the composite function at a specific value (-5).

Thus, we can write and think of the function like this:

f[g(-5)]

So we substitue the -5 for every x in the g(x) function:

g(x) = -5 + 7 = 2

Then we substitute this 2 for every x in the f(x) function:

f(x) = 2^2+7(2) = 4 + 14 = 18