Given the function f(X)=9x+7 , find its inverse

Question

Given the function f(X)=9x+7 , find its inverse

Answer 1

First we must define what it means to be an inverse. If I define a function called "put on my sock" then the inverse would be "take off my sock." This is happening to the foot or the "input." We see that we have

 

f(x)=9x+7

 

This is telling me when I put in the number "x" then first we multiply by 9 then add 7.

 

Now the inverse means we do the inverse thing in the opposite order. The inverse of add 7 is subtract 7 then we take that value and divide 9 instead of multiplying.

 

so that means our inverse should say "Put in the number "x" then subtract 7 then divide 9."

 

The easiest way to do this is to do exactly as Charity said. The end result should say First subtract 7 then divide 9.

Answer 2

hi Trisha,

To find the inverse of this equation, simply switch x and y in your original equation. f(x) is also known as y. So your original equation would be y is equal to 9x+7.

After switching x and y you should get x=9y+7.

now solve for y.

please let me know if you have any questions