McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
9. Perfect Squares
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Exercise 18 Page 69

Is there a greatest common factor? What other factoring technique could be used according to the number of terms?

2(b^2+6b-12)

Practice makes perfect
The greatest common factor (GCF) of an expression is a common factor of the terms in the expression. It is the common factor with the greatest coefficient and the greatest exponent. The GCF of the given expression is 2.
2b^2+12b-24
2(b^2)+ 2(6b)- 2(12)
2(b^2+6b-12)
Note that the expression in the parentheses has three terms. There are two additional common factoring techniques for trinomials.
  1. Perfect Square Trinomials
  2. General Trinomials

Since 12 is not a perfect square, we cannot write the given expression as perfect square trinomial. Let's try the other method. First, we will identify the values a, b, and c. b^2+6b-12 ⇔ 1b^2+ 6b +( -12) For our expression, we have that a= 1, b= 6, and c= - 12. We want to check if we can find a pair of integers with a product of a * c and a sum of b. In this case the product is 1( -12)=-12 and the sum is 6. Let's do it!

Factor Pair Product Sum
-1 and 12 -1* 12 - 12 -1+12 11
1 and -12 1* (-12) -12 1 +(-12) -11
-2 and 6 -2* 6 -12 -2+6 4
2 and -6 2* (-6) -12 2+(-6) -4
-3 and 4 -3* 4 - 12 -3+4 1
3 and -4 3* (-4) - 12 3+(-4) -1

We cannot find a pair of integers whose product is -12 and whose sum is 6. Therefore, we cannot general method for factoring trinomials. The given polynomial cannot be factored, so it is prime.