三道因式分解：急用!（1）5x³-2x²y+8y- - 知识问答

三道因式分解：急用!（1）5x³-2x²y+8y-20x（2）4-16y²-20ay

2个回答

5x³-2x²y+8y-20x
=x²(5x-2y)-4(5x-2y)
=(5x-2y)(x²-2²)
=(5x-2y)(x+2)（x-2）
4-16y²-20ay²+5a
=4(1-4y²)+5a(1-4y²)
=(1-4y²)(4+5a)
=(1+2y)(1-2y)(4+5a)
a³+3a²b+ab²+3b³
=a²(a+3b)+b²(a+3b)
=(a+3b)(a²+b²)

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