Factor 2x^2y - 4xy - 30y? i got up to 2y(x^2 - 2x - 15)?
回答 (5)
2008-08-20 4:45 pm
✔ 最佳答案
1st factor is 2y:= 2x²y - 4xy - 30y
= 2(x²y - 2xy - 15y)
= 2y(x² - 2x - 15)
2nd factor:
x² - 2x = 15
x² - x = 15 + 1
(x - 1)² = 16
x - 1 = 4
x - 1 - 4 = 0
= x - 5
3rd factor:
x - 1 = - 4
x - 1 + 4 = 0
= x + 3
Answer: 2y(x - 5)(x + 3) are the 3 factors.
Proof:
= 2y(x - 5)(x + 3)
= 2y(x² + 3x - 5x - 15)
= 2y(x² - 2x - 15)
= 2x²y - 4xy - 30y
2008-08-20 11:18 pm
=2y(x-5)(x+3)
2008-08-20 11:22 pm
2y( x^2 - 2x -15) = 2y( x^2 -5x +3x -15)
= 2y[ x(x-5) + 3(x-5) ]
= 2y[ (x-5) (x+3) ]
= 2y[ x(x-5) + 3(x-5) ]
= 2y[ (x-5) (x+3) ]
2008-08-20 11:28 pm
2x^2y - 4xy - 30y
= 2(x^2y - 2xy - 15y)
= 2y(x^2 - 2x - 15)
= 2y(x^2 + 3x - 5x - 15)
= 2y(x + 3)(x - 5)
= 2(x^2y - 2xy - 15y)
= 2y(x^2 - 2x - 15)
= 2y(x^2 + 3x - 5x - 15)
= 2y(x + 3)(x - 5)
2008-08-20 11:26 pm
2x^2y - 4xy - 30y
=2x^2y-10xy+6xy-30y
=2xy(x-5)+6y(x-5)
(2xy+6y)(x-5)
2y(x+3)(x-5)
=2x^2y-10xy+6xy-30y
=2xy(x-5)+6y(x-5)
(2xy+6y)(x-5)
2y(x+3)(x-5)
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