已知x y=-8,xy=8,求y-搜答案-智慧作业帮

题目写错应该是求（6xy+7y)+[8x-(5xy-y+6x)]（6xy+7y)+[8x-(5xy-y+6x)]=6xy+7y+8x-5xy+y-6x=xy+2x+8y=xy+2(x+4y)=5+2×

一、x²y-xy²-x+y=56xy(x-y)-(x-y)=56(xy-1)(x-y)=56将xy=8代入：7(x-y)=56x-y=8①又x²+y²=(x-y

x-xy=8(1)xy-y=-9(2)则有(1)-(2):X-XY-XY+Y=X+Y-2XY=8-(-9)=17

yx+xy=xyx+xyy=xy(x+y)xy，∵x+y=8，xy=6，∴原式=6×86=463．

（5X-4Y-3XY）-（8X-Y+2XY）=-(3X+3Y)-5XY=-3*6+4*5=2

-xy（x^2y^5-xy^3-y)=-(xy^2)^3+(xy^2)^2+xy^2=-(-2)^3+4-2=8+4-2=10

由于xy除以x+y=2故xy=2（x+y）将这代入8x-5xy+8y除以-x+3xy-y化简得其中的（x+y）会相互约去故8x-5xy+8y除以-x+3xy-y=-2/5希望这个能帮到你over~

x^2+2xy+y^2=x²+xy+xy+y²=(x²+xy)+(xy+y²)=8+3=11x²-y²=x²+xy-xy-y

解题思路：本题是求整式的值，注意一定要先化简，再求值。化简就是先去括号，在合并同类项。解题过程：解：（6xy+7y）+[8x-（5xy-y+6x）]=（6xy+7y）+[8x-5xy+y-6x]=6x

1/x+1/y=(x+y)/xy=8x+y=8xy2x-3xy+2y/x+2xy+y=[2(x+y)-3xy]/[(x+y)+2xy]=(16xy-3xy)/(8xy+2xy)=13xy/10xy=1

原式=6xy+7y+8x-5xy+y-6x=xy+2x+8y=xy+2(x+4y)=···再问：还有些题哈……

原式=6xy+7y+8x-5xy+y-6x=xy+8y+2x=xy+2(x+4y)=5+2×(-1)=3

6xy+7y）+【8x-（5xy-y+6x）】=xy+8y+2x=xy+2(4y+x)=5-2=3

原式=6xy+7y+8x-5xy+y-6x=xy+2(4y+x)=5-2=3

（6xy+7y)+[8x-(5xy-y+6x)]=6xy+7y+（8x-5xy+y-6x）=6xy+7y+8x-5xy+y-6x=（6xy-5xy）+（7y+y）+（8x-6x）=xy+8y+2x=x

6xy+7y+[8x-5xy+y-6x]=6xy+7y+8x-5xy+y-6x=(6xy-5xy)+(7y+y)+(8x-6x)=xy+8y+2x=xy+2(4y+x)=5-2=3再问：请问x=？y＝

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

将xy=8代入x平方y-8xy平方-x+y=56得8x-8y-x+y=56x-y=8x平方+y平方=(x-y)^2+2xy=8^2+2*8=64+16=80

那9是负的吗～如果不是等于负1,如果是负九等于十七～用第一个等式减第二个等式

原式=-xy²（x²y^4-xy²-1）∵xy²=-2原式=2（（-2)²-（-2）-1）=10