计算 1.(-2x)^3-3x乘(x-2x^2) 2.【(x+2y)^2-(x-2y)(x+2y)】÷4y越快越好

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计算1.(-2x)^3-3x乘(x-2x^2)2.【(x+2y)^2-(x-2y)(x+2y)】÷4y越快越好计算1.(-2x)^3-3x乘(x-2x^2)2.【(x+2y)^2-(x-2y)(x+2

计算 1.(-2x)^3-3x乘(x-2x^2) 2.【(x+2y)^2-(x-2y)(x+2y)】÷4y越快越好
计算 1.(-2x)^3-3x乘(x-2x^2) 2.【(x+2y)^2-(x-2y)(x+2y)】÷4y
越快越好

计算 1.(-2x)^3-3x乘(x-2x^2) 2.【(x+2y)^2-(x-2y)(x+2y)】÷4y越快越好
(1)
(-2x)^3-3x乘(x-2x^2)
=-8x³-3x²+6x³
=-2x³-3x²
=-x²(2x+3)
(2)
[(x+2y)^2-(x-2y)(x+2y)]÷4y
=(x²+2xy+4y²-x²+4y²)/4y
=(2xy+8y²)/4y
=(x+4y)/2

1。原式=-8X^3-3X^2+6X^3
=-2X^3-3X^2
2. 原式={(X+2Y)4Y}/4Y
=X+2Y