f(x)=-5x+4 and g(x)=x^4, choose the expression for
(f^o g)(x)
Answer choices
A. -5x^4+4x^4
B. -5x^4+4
C.-20x^4+16
D.(-5x+4)^4

Question

f(x)=-5x+4 and g(x)=x^4, choose the expression for 
(f^o g)(x) 
Answer choices
A. -5x^4+4x^4
B. -5x^4+4
C.-20x^4+16
D.(-5x+4)^4

decarr432 · Answer

@mathmale

danjs · Answer

f (g(x))

decarr432 · Answer

Okay thanks

mathmale · Answer

(f^o g)(x)  is incorrect, but DanJS's suggestion has taken care of that.

Exactly what does    f(g(x)) mean to you?   What's the name of this combination of two different functions into one function?

danjs · Answer

f(g(x))= -5*g(x) + 4
..
welcome

decarr432 · Answer

Iv'e only been working on this for maybe 20 minutes and I have gotten alot of help but none of this makes sense

mathmale · Answer

You've got to recognize the form     (f o g)(x), which is a "composite function."

As written, or as Dan has written it     f(g(x))   
this composite function is derived by letting function g(x) become the input to function f(x).

Function f(x) is given and is -5x + 4.
Function g(x) is also given and is x^4 (the fourth power of x).

mathmale · Answer

@Decarr432 :     Take f(x) from above.   Write the whole thing out.

                           Now throw out the "x" on both sides of your equation for f(x).  

Would you do that now, please?

decarr432 · Answer

I got the correct answer I pondered it and thought about it and the answer was B

decarr432 · Answer

Thanks for the help, I thought about what you were saying and got the correct answer

mathmale · Answer

Very glad that you got the correct answer!