SOLUTION: Find the inverse function of y=f(x)=7 x-5.

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Question 1104762: Find the inverse function of y=f(x)=7 x-5.
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
7y-5=x
-
7y=x%2B5
y=x%2F7%2B5%2F7

f%5E-1%28x%29=x%2F7%2B5%2F7

Try checking this in the function f(x) and see if the result is x.

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The other tutor showed you the formal algebraic method for finding the inverse: switch the x and y and solve for the new y.

Here is an alternative method that can often be used to find the inverse of relatively simple functions. In cases where it can be used, it is usually a lot less work and therefore much faster than the algebraic method.

This method is based on the concept that the inverse function "undoes" what the function does.

What does the given function do to the input value? It
(1) multiplies it by 7 and then
(2) subtracts 5

To undo that, the inverse function has to do the opposite operations, in the reverse order. So what the inverse function has to do to its input is
(1) add 5 and then
(2) divide by 7

So the inverse function is
y+=+%28x%2B5%29%2F7
or
y+=+x%2F7%2B5%2F7