求两条因式分解答案 1.已知2x^2-5x+1=-1及xy^2=3,求8x^3y^2-20x^2y^2+4xy^21.已知2x^2-5x+1=-1及xy^2=3,求8x^3y^2-20x^2y^2+4xy^2的值2.已知x^2-3x+1=2及xy=7,求6x^2y-2x^3y-2xy的值

分类: 作业答案 • 2021-12-20 12:03:37

问题描述：

求两条因式分解答案 1.已知2x^2-5x+1=-1及xy^2=3,求8x^3y^2-20x^2y^2+4xy^2
1.已知2x^2-5x+1=-1及xy^2=3,求8x^3y^2-20x^2y^2+4xy^2的值
2.已知x^2-3x+1=2及xy=7,求6x^2y-2x^3y-2xy的值

答

8x^3y^2-20x^2y^2+4xy^2
=4xy^2(2x^2-5x+1)
=4*3*(-1)
=-12
6x^2y-2x^3y-2xy
=-2xy(-3x+x^2+1)
=-2*7*2
=-28

答

1、8x^3y^2-20x^2y^2+4xy^2
=4xy²（2x²-5x+1)
=4×3×(-1)
=-12
2、6x^2y-2x^3y-2xy
=2xy(3x-x²-1)
=2×7×[-(x²-3x+1)]
=14×(-2)
=-28