作业帮{x y=28,20x 5y=1160
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/14 07:19:43
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
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^2+xy+y=14y^2+xy+x=28两式相加x^2+y^2+2xy+x+y=42(x+y)^2+(x+y)-42=0(x+y-6)(x+y+7)=0x+y=6或x+y=-7
（1）4x2m+1y的系数是4，次数是2m+2；-5x2y2的系数是-5，次数是4；-31x5y的系数是-31，次数是6；（2）由（1）可得2m+2=8，解得m=3．
正确的解法如下：将已知变形为：xy+3x－y=20x(y+3)－(y+3)=17(x－1)(y+3)=17=1×17=－1×(－17)所以有四种情形：①(x－1)=1(y+3)=17得：x=2,y=1
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
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-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
7或者-8再问：求过程^_^再答：两个等式两边相加
(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
∵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=
x^2-xy=14,(1)xy-y^2=-11,(2)(1)-(2)得：x^2-2xy+y^2=14-(-11)=25
[(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