Teacher2Teacher 
Q&A #104 
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From: Thunder <mrsbinsta@yahoo.com> To: Teacher2Teacher Public Discussion Date: 2002090222:48:53 Subject: Factoring 35x^288x+45 To factor 35x^2  88x + 45 List the factors of the 'a' term vertically: 1 5 7 35 35 7 5 1 List the factors of the 'c' term vertically: 1 3 5 45 15 9 Now cross multiply each set of 'a' factors with each set of 'c' factors. Since 'c' is positive, you ADD these two products to find the sum of 88. I use a giant T to visualize. (If 'c' were negative, you would SUBTRACT the two products.) a = 35  c = 45  1 5 7 35  1 3 5 35 7 5 1  45 15 9  In this case we use the factors: 7  5 5  9 7 x 9 = 63 5 x 5 = 25  88 Now you read the factors across the T as such: (7x  5)(5x  9) Since the 'b' term is negative, the second term in each binomial is also negative.
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