Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
xkiwibird
Posts: 1
Joined: Fri May 01, 2009 3:50 am
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i'm extremely stuck on this problem.
it's y=x2+x.
i know the first step is switching y and x to get x=y2+y, but i don't know what to do afterwards to inverse it, and i am supposed to use the quardatic equation?

Martingale
Posts: 350
Joined: Mon Mar 30, 2009 1:30 pm
Location: USA
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xkiwibird wrote:i'm extremely stuck on this problem.
it's y=x2+x.
i know the first step is switching y and x to get x=y2+y, but i don't know what to do afterwards to inverse it, and i am supposed to use the quardatic equation?

You could try completing the square

stapel_eliz
Posts: 1743
Joined: Mon Dec 08, 2008 4:22 pm
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xkiwibird wrote:it's y=x2+x.
... i don't know what to do afterwards to inverse it, and i am supposed to use the quardatic equation?

You have x2 + x - y = 0, so a = 1, b = 1, and c = -y. Plug these into the Quadratic Formula to solve for x in terms of y. Then swap the variables, etc, etc.