# Math

For what values of b is the expression factorable?
x^2 + bx + 12

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1. (x-p)(x-q) = x^2 + b x + 12
p q = 12
b = +/-(p+q)
p and q must be the same sign and product 12
so
1) p = 1, q = 12
2) p = 3, q = 4
3) p = -1 , q = -12
4) p = -3, q = -4
so
b = 13
b = -13
b = 7
b = -7
try those
x^2 + 13 x + 12 = (x+12)(x+1)
x^2 - 13 x + 12 = (x-12)(x-1)
x^2 + 7 x + 12 = (x+3)(x+4)
x^2 - 7 x + 12 = (x-3)(x-4)
b = -13

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posted by Damon
2. Did we forget 2,6 and -2,-6?

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posted by Steve
3. Thank you Damon and Steve. Thank you both.

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2. 👎 0

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