Math Problem

Question

Find the inverse of the function f (x) =  4x - 5

                                                         --------

                                                          2x + 7

Answer 1

Just follow the standard procedure; call the function x and replace letter x by letter y on the right hand side.

 

Then cross multiply: x(2y+7) = 4y-5

 

Distribute & put all terms on one side, if they contain y, and all non-y terms on other side of equation (remembering to change to opposite signs, of course, when you move a term to the opposite side of the equal symbol).

 

Then factor, getting:  y(2x-4) = -7x - 5

 

Divide out the quantity in parentheses next to y, thus solving for y, which you label as f^-1(x).

 

Answer is: (-7x-5)/(2x-4).

 

 

Answer 2

Hi Ana, 

Step One: Find the inverse of the function by replacing x with y (solve for y).

y=f(x)=4x-5 Switch x and y
x=4y-5 Add 5 to both sides
x+5=4y Divide both sides by 4
y=g(x)=x/4+5/4

Sincerely, 

Starlyte