Question 436134: I need to factor by grouping... if possible can you show step by step and explain a little plz???
(A) 10x^2-45x+6x-27 (B) 3x^3+21x^2-8x-56
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! (A) 10x^2 - 45x + 6x - 27
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Look at the expression, note that the 1st two terms are divisible by 5 and the 2nd two terms are divisible by 3
5(2x^2 - 9x) + 3(2x - 9)
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note that we can factor out x in 1st group, so we have
5x(2x - 9) + 3(2x - 9)
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Note that each group contains (2x - 9), factor that out, and you have
(2x - 9)(5x + 3)
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(B) 3x^3 + 21x^2 - 8x - 56
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Here you see the 1st two term is divisible by 3, the 2nd is divisible by 8:
3(x^3 + 7x^2) - 8(x + 7)
Note here when you factor out -8, it changes the sign to +7
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note that we can factor out x^2 from the 1st group, we have:
3x^2(x + 7) - 8(x + 7)
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now factor out (x+7) and you have left
(x + 7)(3x^2 - 8)
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Did this shed some light on group factoring for you?
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