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Question 701202: I really need help. I am doing something terribly wrong and I do not know how to do this.
x^2+4x-12=0
Thank you very much!
Answer by Simnepi(216)   (Show Source):
You can put this solution on YOUR website! to solve quadratic equations the first thing is to look for factor pairs of the constant term, in this case that is -12.
factors of -12 are: (remember one of these has to be a negative number because negative multiplied by positive gives a negative answer)
plus/minus 1 and 12:
plus/minus 2 and 6:
plus/minus 3 and 4.
Now we look to see if any of those factor pairs can be added to make the coefficient of the x term (that's the number in front of the x) which is +4.
Obviously the factor pair we need are plus/minus 2 and 6 because -2 + 6 = +4
Now we get two brackets and put an x in both and one of the factors in the other
Like this
(x+6)(x-2)
making this equal zero means that either one of these brackets could equal zero, that is
either (x+6)=0 OR (x-2)=0
If x+6=0 then x=-6
Or If x-2=0 then x=2
We do not know which of these solutions is the correct one so we give them both.
That is
x=-6 or x=2
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