当x-3y 4z=1,2x y-2z=2时,化简,的结果为()-搜答案-智慧作业帮

1/X-1/Y=3分子分母同除以xy=(1/y-2-1/x)/(2/y+3-2/x)=(1*3-2)/(2*3+3)=1/9

3x的平方y-【（2xy的平方-2（xy-3/2x的二平方y)+xy]+3xy的立方＝3x²y-(2xy²-2xy+3x²y+xy)+3xy²=3x²

简单啊就1啊再问：为什么再答：你把一带进去-3xy和3xy就抵消了啊所以式子里就不含xy项了啊

再问：非常感谢

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

需要满足-2mxy-1/3xy=0即可由上式可得m=-1/6

3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2

x^4-xy^3-x^3y-3x^2y+3xy^2+y^4=x^4-x^3y-3xy(x-y)+y^4-xy^3=x^3(x-y)-3xy(x-y)-y^3(x-y)=(x-y)(x^3-3xy-y^

x^4-xy^3-x^3y-3x^2y+3xy^2+y^4=（x^4-x^3y）-xy^3+y^4-3x^2y+3xy^2=x^3(x-y)-y^3(x-y)-3xy(x-y)=x^3-y^3-3xy

x^4-xy^3-x^3y-3x^2y+3xy^2+y^4=（x^4-x^3y）-xy^3+y^4-3x^2y+3xy^2=x^3(x-y)-y^3(x-y)-3xy(x-y)=x^3-y^3-3xy

m=3

=3x^2y-2xy^2+2(xy-3/2x^2y)-xy+3xy^2=3x^2y+xy^2+2xy-3x^2y-xy=xy+xy^2=3*(-1/3)+3*1/9=-2/3

(3x-4y+2xy)--(2x--5y+5xy)=3x-4y+2xy-2x+5y-5xy=x+y-3xy=5-3*(-3)=5+9=14

不含xy项就是说含XY的项为0即3kxy+三分之一xy=0解得K=-（1/9）

-2kxy-3xy+(1/2)xy-x+8=[-2k-(5/2)]xy-x+8-2kxy-3xy+(1/2)xy-x+8中不含xy项则xy项前的系数为0-2k-(5/2)=0解得k=-5/4所以k=-

原式=4x²+4xy-24-6x²+3xy=(4-6)x²+(4+3)xy-24=-2x²+7xy-24=-2*1/4+7*1/2*1-24=-21

（1）当1\x-1\y=3时求2x+3xy-2y\x-2xy-y的值=(2/y+3-2/x)/(1/y-2-1/x)=(2×(-3)+3)/(-3-2)=-3/(-5)=3/5;（2）求代数式x四次方

1/x-1/y=2时(y-x)/xy=2y-x=2xy2x+3xy-2y/x-2xy-y=[3xy-2(y-x)]/[-2xy-(y-x)]=-xy/-4xy=1/4

2(xy-5xy的平方)-(3xy的平方-xy)＝2xy-10xy的平方-3xy的平方＋xy＝3xy-13xy的平方当x=-1,y=1时,原式＝-3＋13＝10

(9x^2y-6xy^2)÷(-3xy)-【(4y^2-9x^2)/(-3x+2y)】=-3x+2y-【(2y-3x)（2y+3x）÷(-3x+2y)】=-3x+2y-2y-3x=-6x=-6×（-1