SOLUTION: how do you get the factor form of n^2 - 3n -18

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Question 263136: how do you get the factor form of
n^2 - 3n -18
Found 2 solutions by stanbon, drk:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
how do you get the factor form of
n^2 - 3n -18
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(n-6)(x+3)
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Cheers,
Stan H.

Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
here we want 2 numbers that add to -3 and multiply to -18.
Since the product is - we must use a positive and a negative number.
listing the factor pairs of 18, we get
1, 18
2, 9
3, 6
Notice that if 3 were positive and 6 were negative, we get +3 -6 = -3 which is our middle number.
we now write 2 binomials as
(n - _____)(n - ______)
the blanks are waiting for our numbers +3 and -6. PUtting those in we get
(n+3)(n-6)