作业帮1 2x-1 x y(x²-y² x y 2x),其中x=-2,y=3
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/28 07:13:06
(x+1)(y+1)
求数学达人来解答x²/xy-x/y=(1-x)/y3x/4x+y-x-2y/4x+y=(3x-x-2y)/(4x+y)(1-y/y+x)÷x/y²-x²=(1-y)*(y
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)
对.前提是x不等于y
(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
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?
这题少括号了吧.
1-x-y+xy=(1-x)-(y-xy)=(1-x)-y(1-x)=(1-x)(1-y)
原式=（xy）2+2xy+3-2（x+y）-1-（x+y）2+2（x+y）-1，=（xy）2+2xy+1-（x+y）2，=（xy+1）2-（x+y）2，=（xy+1+x+y）（xy+1-x-y），=（
原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)
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)
解题思路：：∵x+y=0,x+13y=1，解得x=1/12,y=-1/12∴x²+12xy+13y²=1/144-1/12+13/144=14/144-1/12=2/144=1/72解题过程：已知x+
因式分解x²(x+1)-y(xy+x)原式=x³+x²-xy²-xy=x³-xy²+x²-xy=x(x²-y²
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
两式相加得到x+y=5,相减得y-x=1/5,故x=12/5,y=13/5xy=156/25,因为要求的都是正数,而且xy同正负,所以只考虑x,y正数即可故x²+y²=（x+y）^
(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)