Answer:
[tex]y= \frac{-1}{5} x +4[/tex]
Step-by-step explanation:
We can find the inverse function of this excercise, isolating X and then changing the variables.
[tex]y=-5x+20\\y-20=-5x\\\frac{y-20}{-5} =x\\[/tex]
[tex]\frac{y}{-5}-\frac{20}{-5} = x\\\frac{-1}{5}y+\frac{20}{5} =x\\ \frac{-1}{5}y+4 =x[/tex]
And now we change the variables and we get the inverse function:
[tex]y= \frac{-1}{5} x +4[/tex]
