UC知道(x+y+2)(x+y-5)
来源：百度知道 编辑：UC知道 时间：2024/06/08 09:36:44
(x+y+2)(x+y-5)
=x^2+2xy-5x+y^2-5y+2x+2y-10
=x^2+y^2+2xy-3x-3y-10
把（x+y）看作整体
（x+y）^2-3(x+y)-10
拆开即可x^2+y^2+2xy-3x-3y-10
(X+Y+2)(X+Y-5)
=(X+Y+2)(X+Y+2-7) 是让X+Y+2凑成一个整体
=(X+Y+2)(X+Y+2)-7(X+Y+2) 运用乘法的分配率
=以上的答案
(x+y+2)(x+y-5)
=x^2+2xy-5x+y^2-5y+2x+2y-10
=x^2+y^2+2xy-3x-3y-10
(x+y+2)(x+y-5)
3(x+y)-2(x-y)=9 5(x+y)+2(x-y)=-1
(2x+y)(2x-y)-(3x-2y)(x+y)-y(2x-y)
(x-2y)^2+(x-y)(x-2y)-2(x-3y)(x-y)
[(x y)(x-y)-(x+y)^2-2y(x-2y)]/(-2y),其中x=5,y=2003
java int x,y=5;x=++y;if (x==y) x*=2; if (x>y) x++; else x=y-1
x^2+3(x+y)+3-y^2+(x-y)
3X(X-Y)+2Y(X-Y)
(x+y)(x-y)=(x+y)2
3(x+y)(x-y)+4(x-y)^2=?