Can

$\displaystyle \sqrt{9-x^2}$

be simplified to

$\displaystyle 3-x$

?

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- Sep 21st 2009, 04:33 PMabsvaluesimplifying under a radical
Can

$\displaystyle \sqrt{9-x^2}$

be simplified to

$\displaystyle 3-x$

? - Sep 21st 2009, 05:04 PMI-Think
No, because $\displaystyle 9-x^2=(3-x)(3+x)$

So$\displaystyle \sqrt{9-x^2}=\sqrt{(3-x)(3+x)}$

You can even put in a number to test.

Let $\displaystyle x=1$

For $\displaystyle x=1$

$\displaystyle \sqrt{9-x^2}=2\sqrt{2}$

While

$\displaystyle 3-x=2$