Question

Given f(x)=4x^2-x and g(x)=2x^2 find f(g(x))

Answer 1

f( x )= 4 * x^2 - x

f ( g( x) ) = f( 2x^2 ) = 4 * (2x^2) ^2 - ( 2x^2) = ?


Whatever f did to x; in this case, squared it, multiplied by 4 and then subtracted it,

f does those same operations t o ( 2 x^2) which now plays the role of x.

Answer 2

i had that and ended up with 2x(4x^3-x), which is wrong

Answer 3

Let me see what I get.

Answer 4

I got 16 x^4 - 2x^2

Answer 5

Look at this again:

4 * (2x^2) ^2 - ( 2x^2) =

Answer 6

oh crud..

(2x^2)^2=4x^4...

Dang, I put 2x^4 on my test.

Answer 7

Yikes.

Answer 8

So would 16x^4-2x^2 be the final answer, or should I factor the gcf?

Answer 9

I don't know that there is a set policy on that.

I think that I would.