Homework Help: Math (Grade 12)

Posted by Lucy on Wednesday, September 17, 2008 at 5:50pm.

I need help with this problem (composite functions):
If f(x) = 4x-3 and h(x )= 4x^2-21, find a function g such that f(g(x)) = h.

I don't understand how we're supposed to combine the functions.

Oh, and the answer is supposed to be g(x) = x^2 - (9/2).

Thanks!

Math (Grade 12) - bobpursley, Wednesday, September 17, 2008 at 5:55pm
I was reading, and got the answer in my head before I read your answer line.

It is easy.

f(x) is given. 4x-3 YOu want 4x^2-21

so what times 4 will equal 4x^2? Ans x^2

Now what times 4 will equal -21 when you add -3? 4z-3=-21
4z=-18
z=-9/2

so g(x)=x^2 -9/2
Math (Grade 12) - Ahmed, Wednesday, January 16, 2013 at 12:07pm
4 x 3 = 12
21 – 2 = 19
4 x 2 = 8
5 x 4 = 20
2 + 1 = 3
14 x 12 = 168
4 x 12 = 48
2 + 4 = 6
Math (Grade 12) - Ahmed, Wednesday, January 16, 2013 at 12:07pm
4 x 3 = 12
21 – 2 = 19
4 x 2 = 8
5 x 4 = 20
2 + 1 = 3
14 x 12 = 168
4 x 12 = 48
2 + 4 = 6

Answer this Question

Related Questions

Math (Composite Functions) - I don't understand this question at all. If f(x...
Compisiton of Functions - Let f(x) = x + 4 and h(x) = 4x - 1 Find a function &...
math - how to you find a composite function form of y in this problem? y = 1/[(x...
Composite Functions - Find the composite functions for the given functions. (6 ...
Polynomial Fucntion Problem - Could you help me with the following problem, I ...
Math - Find the requested function and state its domain: f(x)= 4x+3 g(x)=4x-5 ...
Math - Find the requested function and state its domain: f(x)= 4x+3 g(x)=4x-5 ...
Simplifying Rational Expressions - Can someone PLEASE solve these for me 1.4x-12...
Calculus - Find a function g such that g 0 (x) = sin(ln x 3 ( 4x . How many such...
derivative - 29) Find the derivative of the function. F(X)=2x^2(3-4x)^2 This is...

For Further Reading

First Name:
School Subject:
Answer: