SOLUTION: I could really use help on this question. x^2+x-2=0

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Question 110339: I could really use help on this question.
x^2+x-2=0
Found 2 solutions by scott8148, jim_thompson5910:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
(x+2)(x-1)=0

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:


Starting with the general quadratic


ax%5E2%2Bbx%2Bc=0


the general solution using the quadratic equation is:


x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29




So lets solve x%5E2%2Bx-2=0 ( notice a=1, b=1, and c=-2)





x+=+%28-1+%2B-+sqrt%28+%281%29%5E2-4%2A1%2A-2+%29%29%2F%282%2A1%29 Plug in a=1, b=1, and c=-2




x+=+%28-1+%2B-+sqrt%28+1-4%2A1%2A-2+%29%29%2F%282%2A1%29 Square 1 to get 1




x+=+%28-1+%2B-+sqrt%28+1%2B8+%29%29%2F%282%2A1%29 Multiply -4%2A-2%2A1 to get 8




x+=+%28-1+%2B-+sqrt%28+9+%29%29%2F%282%2A1%29 Combine like terms in the radicand (everything under the square root)




x+=+%28-1+%2B-+3%29%2F%282%2A1%29 Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




x+=+%28-1+%2B-+3%29%2F2 Multiply 2 and 1 to get 2


So now the expression breaks down into two parts


x+=+%28-1+%2B+3%29%2F2 or x+=+%28-1+-+3%29%2F2


Lets look at the first part:


x=%28-1+%2B+3%29%2F2


x=2%2F2 Add the terms in the numerator

x=1 Divide


So one answer is

x=1




Now lets look at the second part:


x=%28-1+-+3%29%2F2


x=-4%2F2 Subtract the terms in the numerator

x=-2 Divide


So another answer is

x=-2


So our solutions are:

x=1 or x=-2