Given $f(x) = (2x)/(x+3)$ , how do you find $f^(-1) (4)$ ?

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Given $f(x) = (2x)/(x+3)$ , how do you find $f^(-1) (4)$ ?

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Answer 1 · 2015-08-07T14:54:11

I found: $f^-1(4)=-6$

Explanation:

I start rearranging the original function $y=f(x)=(2x)/(x+3)$ solving it for $x$ to get:
$(x+3)*y=2x$
$xy+3y-2x=0$
$xy-2x=-3y$
$x(y-2)=-3y$
and:
$x=f(y)=(-3y)/(y-2)$ or changing $x$ with $y$ you get:
$f^-1(x)=(-3x)/(x-2)$
and
$f^-1(4)=(-3*4)/(4-2)=-12/2=-6$

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Given $f(x) = (2x)/(x+3)$ , how do you find $f^(-1) (4)$ ?

1 Answer

Explanation:

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Given f(x) = (2x)/(x+3)f(x) = (2x)/(x+3), how do you find f^(-1) (4)f^(-1) (4)?

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Explanation:

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Given $f(x) = (2x)/(x+3)$ , how do you find $f^(-1) (4)$ ?