# inverse question help!

• Sep 16th 2008, 03:22 PM
imthatgirl
inverse question help!
how do you find the inverse funtion of (3x-2)^2=17 for x≥ 2/3

i know you are suppose to issolate for x then switch x and y but i did that and didnt get the answer provided with the book.
their answer was x= √(17)/3 + 2/3

can someone show me in steps?
• Sep 16th 2008, 03:37 PM
icemanfan
You need a function, not an equation, in order to find an inverse. What is the function for which you are being asked to find the inverse?
• Sep 16th 2008, 03:49 PM
imthatgirl
it just says solve each equations by finding an inverse funtion
• Sep 16th 2008, 03:58 PM
icemanfan
All right. Suppose the function is f(x) where $\displaystyle f(x) = (3x-2)^2$. This is how to find the inverse: Write it as $\displaystyle y = (3x-2)^2$ and then interchange x and y: $\displaystyle x = (3y-2)^2$.

Now take the square root of both sides: $\displaystyle \sqrt{x} = 3y - 2$

Add two to both sides: $\displaystyle \sqrt{x} + 2 = 3y$

Divide both sides by 3: $\displaystyle \frac{\sqrt{x} + 2}{3} = y$

So that is your inverse function.