Algebra Review Chapter 16

Question

Find the inverse:

f(x)= 5x-15

Answer 1

To find the inverse of an equation we are going to swap the x and y(fx) values.

So we switch this ...y=5x-15

to... x=5y+15

Then Solve for y

Get 5y to the left so subtract....

x-5y=15

Subtract x to get it moves to the right.

-5y=-x+15

Then lastly divide by -5 on both sides so that y is by itself.

y=(1/5)x+3

Change y back to f(x) for any test that you may have.

f(x)=(1/5)x+3

Answer 2

y=5x -15

switch x and y

x=5y -15, solve for y

5y =x+15

y = x/5 +3

f^-1(x) = x/5 + 3