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November 20, 2014

November 20, 2014

Posted by **David** on Wednesday, December 12, 2012 at 2:58pm.

X^2-4x=21

- Math Help now !!!! Plz -
**drwls**, Wednesday, December 12, 2012 at 5:34pmLearn the quadratic formula:

x = [-b +/-sqrt(b^2 -4ac)]/2a

In your case a = 1, b = -4 and c = -21

x = [4 +/-sqrt(100)]/2

You finish it. You surely know what the square root of 100 is.

.

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