Question 253136: How do you factor 3x squared + 31x + 36
Found 2 solutions by Alan3354, Greenfinch:
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! 3x squared + 31x + 36
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The 1st terms are 1 and 3.
There are no minus signs, so it's
(3x + a)*(x + b)
a and b can be:
1 and 36 (this won't work, 36 is too much, >31)
2 and 18
3 and 12
4 and 9
6 and 6
Either a or b has to be an odd number, they can't both be even since 31 is odd.
That leaves:
3 and 12
4 and 9
--> (3x + 4)*(x + 9)
Answer by Greenfinch(383)  (Show Source):
You can put this solution on YOUR website! Factors of 3 are 3 and 1
Factors of 36 are 1,36: 2,18: 3,12: 4,9: 6,6
We need a way to get these to add to 31. The obvious try is 3 x 9 and 4 x 1
So the factors are (3x + 9)(x + 4)= 0
Therefore x = -3 or -4
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