聪明的人帮我 1.(x+y)(x-y)-(x-y)² 2.(3a-2b)²-(3a+2b)² 3.2(x+1)²-½(x+2)(x-3)
问题描述：
聪明的人帮我 1.(x+y)(x-y)-(x-y)² 2.(3a-2b)²-(3a+2b)² 3.2(x+1)²-½(x+2)(x-3)
写的清楚点 分不多 4.(2x-y)²-4(x-y)(x+2y) 5.(x-2y+4)(x+2y-4)
答
1,x^2-y^2-x^2-y^2+2xy=2xy2,9a^2+4b^2-12ab-9a^2-4b^2-12ab=-24ab3,2x^2+2+4x-1/2(x^2-x-6)=2x^2/3+9x/2+54,4x^2-4xy+y^2-4x^2+8y^2-4xy=9y^2-8xy5,x^2-4y^2-16+16y