Rewrite the equation 4x - 10y = 11 as a function of x 

Rule:
1. Solve for y.
2. Replace y by f(x)

               4x - 10y = 11

Add -4x to both sides

                   -10y = 11 - 4x

Multiply every term by -1 so the term on left will be positive. 

                    10y = -11 + 4x

Swapping the terms on the right eliminates the need for a  
sign in front of the expression. 

                    10y = 4x - 11

Divide both sides by 10

                 =    

Cancel the 10's on the left, and you have

                             y = 

Now all you do is replace the letter "y" by "f(x)"

                          f(x) = 

That's the answer. 

Edwin