Question

f(x) = 3x + 6, g(x) = 2x^2

Find (fg)(x).

please help

Answer 1

What is f(3)?

Answer 2

what do you mean ?

Answer 3

Evaluate f(3).

Answer 4

so 3=3x+6 evaluate that ?

Answer 5

f(3) = 3(3) + 6 -- Perfect.

Harder one.

Evaluate f(Fred)

Answer 6

how do i do that one ?

Answer 7

Exactly the same way. This was my point.

f(Fred) = 3(Fred) + 6

Do you see that this is so?

Answer 8

u just join it is 6x^3+12x^2

Answer 9

Don't get ahead of me.

First, though, what does (fg)(x) mean? Is it f(g(x)) or f(x)*g(x)?

Answer 10

Anyway, f(g(x)) = 3(g(x)) + 6 = 3(2x^2) + 6 = 6x^2 + 6