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PLEEAASSEE HELP!!!

The square of a number exceeds that number by 12. What are the two possible solutions?

3 or -4
3 or 4
-3 or 4

Please explain if you can!!

User Ashox
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1 Answer

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Let's call the number x. The square of a number would be
x^(2). This is 12 more than the number itself. 12 more than the number is 12+x.

Putting this together we get
x^(2) =x+12
This is a quadratic equation so we set it equal to zero by subtracting x+12 from both sides. We obtain:


x^(2) -x-12=0

The left-had side factors as such:
(x-4)(x+3)=0

Since we have two expressions that when multiplied give zero either one or both equal zero. We set each equal to zero to obtain the solutions:

x-4=0 so x =4
and

x+3=0 so x=-3

The two solutions are 4 and -3
User Heero
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