SOLUTION: how do you factor x squared minus x minus 40?

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Question 1064352: how do you factor x squared minus x minus 40?
Answer by josgarithmetic(39613) About Me  (Show Source):
You can put this solution on YOUR website!
x^2-x-40
x%5E2-x-40, wanted as (x+r)(x+s).

Can you find two number, INTEGERS, so that r+s=-1 and rs=-40 ?
1 & 40?
2 & 20?
4 & 10?
5 & 8?
None of these combinations will work.

Alternative: Check discriminant.
%28-1%29%5E2-4%2A1%2A%28-40%29
1%2B160
161
This is not a perfect square (based on integers...)

Not factorable.