SOLUTION: F(x)=x^2-3x g(x)=2x+4 What is the value of: F(g^-1(-4)) Can you please help me with this problem? I am having trouble with functions.

Algebra.Com
Question 551596: F(x)=x^2-3x
g(x)=2x+4
What is the value of:
F(g^-1(-4))
Can you please help me with this problem? I am having trouble with functions.

Answer by nerdybill(7384)   (Show Source): You can put this solution on YOUR website!
F(x)=x^2-3x
g(x)=2x+4
What is the value of:
F(g^-1(-4))
.
Begin by finding:g^-1(x)
g(x)=2x+4
y=2x+4
switch the variables and solve for y:
x=2y+4
x-4=2y
x/2 - 2 = y (this is g^-1(x))
.
Now, find:
g^-1(-4) = 4/2 - 2
g^-1(-4) = 2 - 2
g^-1(-4) = 0
.
Finally, we can find:
F(g^-1(-4))
F(0)
F(0)=0^2-30 = 0-0 = 0
.
Solution: 0




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