(1)由(x+2)2+|y-3|=0,可得x+2=0,y-3=0,即x=-2,y=3,∴原式=3x2y+5x-5x2y+4x=-2x2y+9x,当x=-2,y=3时,原式=-2x2y+9x=-2×(-2)2×3+9×(-2)=-24-18=-42;(2)原式=2x3-3x2y-2xy2-x3+2xy2-y3-x3+3x2y-y3=-2y3,∵所得结果与x的取值没有关系,∴他将“x= 1 2 ”错抄成“x=- 1 2 ”后,所得结果也是正确的,当y=-1时,原式=2.