Question

Let f(x) = -­2x ­- 7 and g(x) = ­-4x + 3. Find (f o g)(-­5)

A.
3

B.
-53

C.
-9

D.
23

Answer 1

f(x) = – 2x – 7 and g(x) = – 4x +3.


Finding g(–5):

g(–5) = – 4 · (– 5) + 3

g(–5) = 20 + 3

g(–5) = 23


So,

(f o g)(– 5) = f[ g(– 5) ]

(f o g)(– 5) = f(23)

(f o g)(– 5) = – 2 · 23 – 7

(f o g)(– 5) = – 46 – 7

(f o g)(– 5) = – 53 <——— this is the answer (option B. – 53)


I hope this helps. =)