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18 votes
18 votes
7. Let f(x) = 3x and g(x) = (x + 2)^2. Find the value of (f og)(-5)A.135B. -27 C. 169. D.27.

User Cexbrayat
by
2.7k points

1 Answer

15 votes
15 votes

Answer:

D.27

Explanation:

This is a question of composite functions.

(fog)(x) = f(g(x)).

We have that:

f(x) = 3x

g(x) = (x+2)²

To find f(g(x)), we replace each x in f(x) by g(x), which is (x+2)². So

f(g(x)) = f((x+2)²)=3(x+2)²

At x = -5

f(g(-5)) = 3(-5+2)² = 3*(-3)²=3*9 = 27

The correct answer is D.27

User Cefstat
by
3.2k points
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