radical equation problem help
$\displaystyle \sqrt{x+7}-2\sqrt{x}=-2$
$\displaystyle \left(\sqrt{x+7}\right)^2=\left(-2+2\sqrt{x}\right)^2$
$\displaystyle x+7=4-8\sqrt{x}+4x$
$\displaystyle \left(-3x-3\right)^2=\left(-8\sqrt{x}\right)^2$
$\displaystyle 9x^2+18x+9=64x$
$\displaystyle 9x^2-46x+9=0$
iam lost after that, reviewed it and cant figure out what went wrong, the answer is 9
Re: radical equation problem help
Quote:
Originally Posted by
mathmathmathmathmathmathm 
$\displaystyle \sqrt{x+7}-2\sqrt{x}=-2$
$\displaystyle \left(\sqrt{x+7}\right)^2=\left(-2+2\sqrt{x}\right)^2$
$\displaystyle x+7=4-8\sqrt{x}+4x$
$\displaystyle \left(-3x-3\right)^2=\left(-8\sqrt{x}\right)^2$ this line ... should be (-3x+3)^2 on the left side
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