SOLUTION: I need quick help with this question f(x)=4x f(f^-1(-6))

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Question 765455: I need quick help with this question
f(x)=4x
f(f^-1(-6))
Found 2 solutions by jim_thompson5910, MathLover1:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
f(x) is a linear function. So it is one-to-one which means it has an inverse. So f^(-1) exists and there are no restrictions on the inverse (because f(x) is one-to-one throughout its domain)

Because there are no restrictions on the inverse at all, we know that f(f^(-1)(x)) = x for all values of x


So, f(f^-1(-6)) = -6

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=4x first find f%5E-1
y=4x..switch x and y
x=4y.....solve for y
x%2F4=y
so,
f%5E-1+%28x%29+=+x%2F4
now find f%28f%5E-1%28-6%29%29
f%5E-1+%28-6%29+=+4%28-6%2F4%29
f%5E-1+%28-6%29=-6