Question 359316
Examples:
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X^2-9=0
(X+3)(X-3)=0
X+3=0
X=-3 ANS.
X-3=0
X=3 ANS.
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X^2+4X-21=0
(X+7)(X-3)=0
X+7=0
X=-7 ANS.
X-3=0
X=3 ANS.