Question

If f(x) = 5x, what is f–1(x)?

Answer 1

it woud be i think f-5x

Answer 2

$\bold{\frac{5}{x}}$ is the value of $\bold{f^{-1}(x)}$.  

Given:

f(x) = 5x  

To find:

$f^{-1}(x)=?$

Solution:

f(x)=5 x--(1)

Put y=f(x) in equation (1)

y=5 x

Which means that the equation is given in terms of x, we have to find the equation in terms of y i.e., $f^{-1}(x)$

So to find the value of the function in terms of y, we simplify

y=5 x ; $x=\frac{5}{y}$

After simplifying the function, now switch the value of y and x in the function in $x=\frac{5}{y}$

$x=\frac{5}{y}$changes into $y=\frac{5}{x}$

The value of the $\bold{f^{-1}(x)=\frac{5}{x}}$.