Question 531598: How do I factor:
7-6b-b^2=
? Thank you
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! How do I factor:
7-6b-b^2=
We usually write it
-b^2 - 6b + 7 = 0
Easier to factor if b^2 is positive, multiply by -1 and you have
b^2 + 6b - 7 = 0
-7 only has two possible factors, we know one is neg and one positive
(b _ 1)(b _ 7) = 0
Choose the signs that will give you 6 as the coefficient of b
(b - 1)(b + 7) = 0
:
Check this by FOILing (b+7)(b-1) = b^2 - b + 7b - 7 = b^2 + 6b - 7
Multiply by -1 to get the original problem -b^2 - 6b + 7
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