作业帮10x 5y=170,x y=20
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/16 11:42:43
根据题意得，x+1=0，2x-y+4=0，解得x=-1，y=2，∴x5y+xy5=（-1）5×2+（-1）×25=-2-32=-34．故答案为：-34．
[2x(x²y-xy²)+xy(xy-x²)]/x²y=[2x^3y-2x^2y^2+x^2y^2-x^3y]/x²y=x-y=4
[(xy+2)(xy+2)-2(xy+1)+2]÷(xy)=[(xy+2)(xy+2)-2xy-2+2]÷(xy)=[(xy+2)(xy+2)-2xy]÷(xy)=[(xy)^2+4xy+4-2xy]
[（xy+2）（xy-2）-2x2y2+4]÷（xy）=（x2y2-4-2x2y2+4）÷xy=-x2y2÷xy=-xy,当x=10,y=1/25时,原式=-2/5．
[(xy+2)(xy-2)-2x^2y^2+4]/(xy)=[(x^2y^2-4)-2x^2y^2+4]/(xy)=-x^2y^2/xy=-xy=-10*(-1/25)=2/5
[（xy-2)²+4xy-4]÷(xy)=(x²y²-4xy+4+4xy-4)÷(xy)=x²y²÷xy=xy=10×1/25=2/5
2xy=10xy=5
xdy=(y+xy)dxdy/y=((1+x)/x)dxln|y|=ln|x|+x+cy=±e^(ln|x|+x+c)其中c是常数再问：真还不理解我们是选择题：y=cxe^xy=c+x-x^2y=cs
(x-xy)+(xy-y)=40-20x-xy+xy-y=20x-y=20(x-xy)-(xy-y)=40-(-20)x-xy-xy+y=60x+y-2xy=60
1、已知2x²+xy=10,3y²+2xy=6,求4x²+8xy+9y²的值为?分析：通过观察,可以把8xy拆成2xy+6xy,分别于剩余的两项组合,并提取公因
(3x^2+2xy)/xy-(2x^2-xy)/xy=(3x^2+2xy-2x^2+xy)/xy=(x^2+3xy)/xy=x(x+3y)/xy=(x+3y)/y
xy+yx=10x+y+10y+x=11x+11y=100+x10x=100-11yx=10-1.1y所以y只能是0
∵x^2-xy=10∵xy-y^2=20∴（x^2-xy）+（xy-y^2）=30∴x^2-y^2=30∵x^2-xy=10∵xy-y^2=20∴（x^2-xy）-（xy-y^2）=x^-2xy+y^
由题意得：X＝Y+2.那么Y（Y+2）+Y+2＝20（Y+2）×（Y+1)=20所以y＝3那么x＝5可待入xy+y=18就不对了.（Y+2）×（Y+1)=20,Y应该是-6,X是-4,答案就对了.X＝
3-4x-4xy+1/2xy+1/2y=3-80+1/2xy+1/2y=3-80-5=-82x-y=(x+xy)-(xy+y)=20+10=30x+2xy+y=(x+xy)+(xy+y)=20-10=
[(xy-2)(-xy-2)-4(xy-1)^2]除以(-xy)=[-x²y²+4-4(x²y²-2xy+1)]÷(-xy)=(-x²y²+
再问：能把第三题重新发一遍吗？再答：这三个题本质上式连在一起的再答：这道题应该是希望杯的试题
x-y=(x-xy)+(xy-y)=40+(-20)=20x+y-2xy=(x-xy)-(xy-y)=60
即(10x+y)*(10y+x)=2268101xy+10x²+10y²=2268因为后面的10x²+10y²只可能是整十的数,所以2268中的个位8要靠101