SOLUTION: inverse of y=log(x-7)

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Question 1111671: inverse of y=log(x-7)
Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


(1) A formal algebraic process for finding the inverse of a function: switch x and y and solve for the new y:
x+=+log%28%28y-7%29%29
10%5Ex+=+y-7
10%5Ex%2B7+=+y

The inverse is y+=+10%5Ex%2B7.

(2) A different way to find an inverse, if the function is relatively simple:

Since an inverse function "un-does" what the function does, determine what operations were performed on the input by the original function; the inverse function will perform the inverse operations in the opposite order.

For this example, the operations performed on the input by the original function are
(1) subtract 7
(2) take log base 10

The inverse operations, in the opposite order, are
(1) raise 10 to the power
(2) add 7

The inverse is y=10%5Ex%2B7