Question 176268
First, you need to find the inverse function for f.  This is done by first replacing f(x) with y,
{{{y=4-3x}}}
Next, you swap the two variables.
{{{x=4-3y}}}
And lastly, you solve for y so that it is in y= format again.
{{{x-4=-3y}}}
{{{y=(-1/3)x+4/3}}}
This is the inverse function:
{{{f^-1x=(-1/3)x+4/3}}}
So if we want to evaluate the inverse function at -41, we just plug in -41 for x now and obtain that
f^(-1)(-41)=(-1/3)(-41)+4/3=(41/3)+4/3=45/3=15