If f(x) = 4x – 1 and g(x) = x2 + 2x + 2, what is f(g(x))? can some explain. I keep getting the wrong answer...

x2 + 8x – 2

x2 + 6x + 1

4x2 + 6x – 1

4x2 + 8x + 7

Question

If f(x) = 4x – 1 and g(x) = x2 + 2x + 2, what is f(g(x))? can some explain. I keep getting the wrong answer...

 x2 + 8x – 2 

 x2 + 6x + 1 

 4x2 + 6x – 1 

 4x2 + 8x + 7

parthkohli · Answer

Pre-note: $f(g(x)) \ne f(x) \times g(x)$

parthkohli · Answer

$ \color{Black}{\Rightarrow f(g(x)) = f(x^2 + 2x + 2) = 4(x^2 + 2x + 2) - 1}$

parthkohli · Answer

Does that make it easier for you to complete the rest?

anonymous · Answer

f(x)=4x-1
here x is variable
like f(t)=4t-1
Therefore f(g(x))=4(x^2+2x+2)-1
=4x^2+8x+7. ur ans seems to be right

anonymous · Answer

okay ty I wasn't sure.

parthkohli · Answer

You're welcome!