8x的平方-【3x+5(2x的平方-3x)+3】-2(3x-2)
=8x²-(3x+10x²-15x+3)-6x+4
=8x²-(10x²-12x+3)-6x+4
=8x²-10x²+12x-3-6x+4
=-2x²+6x+1
(4x-2y)-{5x-[8y-2x-(x+y)]-x}
=4x-2y-(4x-8y+2x+x+y)
=4x-2y-(7x-7y)
=4x-2y-7x+7y
=-3x+5y