3x-y=35-x y就等于-搜答案-智慧作业帮

x²+y²+6xy=x²+y²+2xy+4xy=(x+y)²+4xy=2²+4×3=4+12=16

x²+y²=(x+y)²-2xy=(-5)²-2×3=25-6=19很高兴为您解答,祝你学习进步!如果有其他问题请另发或点击向我求助,请谅解,谢谢!有不明白的可

x²y+xy²=xy(x+y)=(-3)*6=-18

题目有问题

x-3xy-Y分之3x+5xy-3y==(3x+5xy-3y)/(x-3xy-Y)=(5+3*(1/y-1/x))/(-3+(1/y-1/x)).分子分母同时除以xy=(5-21)/(-3-7).将x

XY=1,x=y所以x^2=1得x=y=1或-1当x=y=1时x^2-3y+1=-1当x=y=-1时x^2-3y+1=5

-5x+2-3xy-5y因为xy=1所以原式=-5x-5y-1-5（x+y)-1因为x+y=3所以-15-1=-16

先化简,再求值3x²y-[2xy-2(xy-2/3x²y)+xy]=3x²y-2xy+2(xy-2/3x²y)-xy=3x²y-2xy+2xy-4/3

原式可化简为xy(-x^2-y^2+2xy)=xy(-x^2-y^2-2xy+4xy)=xy(-(x+y)^2+4xy)注：-x^2-y^2-2xy=-（x+y）将1,2式代入得,3*（-（-5）^2

x、y都是整数吧?就按这个解答.方程化为(x-1)(y+1)=17,由于17=1*17=(-1)*(-17),且x、y都是整数,因此可得（1）x-1=1,y+1=17,解得x=2,y=16；（2）x-

4xy=(x+y)^2-(x-y)^2xy=〔(x+y)^2-(x-y)^2〕÷4运用这个,在进行计算.

2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3（x+y）+2xy=3*（-2）+2*3=0

2.25再答：x=1.5,y=1.50

3x²-xy+y²=101-xy+4y²=421-2得3x²-3y²=6x²-y²=2选B

2分之1或负4分之3

1/x-1/y=3则x-y=-3xyx-3xy-y/2x-xy-2y=(-3xy-3xy)/(-6xy-xy)=6/7

（x+2y-xy)-(-2x-y+xy)=x+2y-xy+2x+y-xy=3x+3y-2xy=3(x+y)-2xy=3×0.5-2×(-0.5)=1.5+1=2.5

1/x-1/y=2(y-x)/xy=2y-x=2xy(3x+5xy-3y)/(x-xy-y)=[5xy-3(y-x)]/[-xy-(y-x)]=(5xy-6xy)/(-xy-2xy)=-xy/-3xy

|x-y|=4,xy=-3(x+y)^2=(x-y)^2+4xy=14-12=2x+y=根2,-根2xy^2+x^2y=xy(x+y)=-3根2,3根2再问：(x+y)^2=(x-y)^2+4xy=1

∵x=2,y=3∴2(xy^2+3y^3-x^2y)-(-2x^2y+y^3+xy^2)-4y^3=2xy²+6y³-2x²y+2x²y-y³-xy&