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Giveng(x) is the inverse of f(x), andf(-4)= 9, what is the value of:8(9) – 3f (-4)?

Giveng(x) is the inverse of f(x), andf(-4)= 9, what is the value of:8(9) – 3f (-4)?-example-1
User Brian Le
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1 Answer

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It is given that the function g(x) is the inverse of f(x) so it follows:


g(x)=f^(-1)(x)

It is given that f(-4)=9 so it follows:


\begin{gathered} f(-4)=9 \\ f^(-1)f(-4)=f^(-1)(9) \\ -4=g(9) \end{gathered}

So the value of g(9)-3f(-4) is given by:


\begin{gathered} g(9)-3f(-4)=-4-3(9) \\ =-4-27 \\ =-31 \end{gathered}

Hence the value is -31.

User Rik
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