作业帮x-y 21,x y-1
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/09 16:17:15
(x+1)(y+1)
xy(xy+1)+(xy+3)-2(x+y+1/2)-(x+y-1)^2=xy(xy+1)+(xy+1)+2-2(x+y)-1-[(x+y)^2-2(x+y)+1]=(xy+1)^2+2-2(x+y)
1.2(Xy+Xy)-3(Xy-xy)-4Xy=2*2xy-0-4xy=4xy-4xy=02.1/2ab-5aC-(3acb)+(3aC-4aC)=1/2ab-5ac-3acb-ac=1/2ab-6a
(x+y-2xy)(x+y-2)+(1-xy)^2=(x+y)^2-2(1+xy)(x+y)+4xy+1-2xy+x^2y^2=(x+y)^2-2(1+xy)(x+y)+(1+xy)^2=(x+y)^
3xy[2xy-x(y-2)+x-1]=3xy(2xy-xy+2x+x-1)=3xy(xy+3x-1)=3x^2y^2+9x^2y-3xy
18(4x²-xy)-19(4x²-xy)+(4x²-xy-1)=72x²-18xy-76x²+19xy+4x²-xy-1=-4x²
xy-1+x-y=XY+X-Y-1(加法交换律）=（XY+X）－（Y＋1）＝X（Y＋1）－(Y+1)（提取公因式X）=(Y+1)(X-1)（提取公因式Y+1）这样可以么?
由题设可知y=xy-1，∴x=yx3y=x4y-1，∴4y-1=1，故y=12，∴12x=x，解得x=4，于是x+y=4+12=92．故答案为：92．
1-x-y+xy=(1-x)-(y-xy)=(1-x)-y(1-x)=(1-x)(1-y)
原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)
原式=1-3xy+x+(-4x-6xy)=1-3xy+x-4x-6xy=1-3x-9xy
xy+1/xy+y/x+x/y=[(xy)^2+1+x^2+y^2]/(xy)=[(xy)^2-2xy+1+x^2-2xy+y^2+4xy]/(xy)=[(xy-1)^2+(x-y)^2+4xy]/(
xy-x-y+1=x(y-1)-y+1=x(y-1)-(y-1)=(y-1)(x-1)
因式分解x²(x+1)-y(xy+x)原式=x³+x²-xy²-xy=x³-xy²+x²-xy=x(x²-y²
设t=xy+1;(xy+1)(x+1)(y+1)+xy=t(x+1)(y+1)+xy=t(xy+x+y+1)+xy=t(t+x+y)+xy=t^2+xt+yt+xy=(t+x)(t+y)-xy+xy=
xy+1/xy>=2√（xy*1/xy）=2(当xy=1/xy即xy=1时取等号)x/y+y/x>=2√（x/y*y/x）=2(当x/y=y/x即x=y取等号)当x=y=1时可以同时满足两项的等号要求
(xy+1)(x+1)(y+1)+xy展开(x+1)(y+1)展开,得(xy+1)(xy+x+y+1)+xy即(xy+1)(xy+1+x+y)+xy将(xy+1)当做一个整体,展开得(xy+1)^2+
(x-1)(y-1)
原式=(x+y)(x+y)+2(x+y)xy+(xy)^2-1^2=(x+y)^2+2(x+y)xy+(xy)^2-1=(x+y+xy)^2-1=(x+y+xy-1)(x+y+xy+1)=(x+y+x
解:原式=xy+y-x-1=y(x+1)-(x+1)=(x+1)(y-1)