(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