SOLUTION: f(x) = 7x + 4, find a formula for f^-1(x) f^-1(x)=

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Question 725031: f(x) = 7x + 4, find a formula for f^-1(x)
f^-1(x)=
Answer by josgarithmetic(39613) About Me  (Show Source):
You can put this solution on YOUR website!
The fast way to find the inverse is like this:
y=7x%2B4,
Switch x and y positions,
x=7y%2B4,
Solve for y,
7y%2B4=x
7y=x-4
y=%281%2F7%29x-4%2F7, meaning %28f%28x%29%29%5E-1=%281%2F7%29x-4%2F7

That was not very formal but for linear equations of lines is effective enough.