早教吧作业答案频道 -->数学-->
化简求值:(xy^-1-x^-1y)/(x^-1+y^-1),其中x=2,y=-1
题目详情
化简求值:(xy^-1-x^-1y)/(x^-1+y^-1),其中x=2,y=-1
▼优质解答
答案和解析
解
(xy^-1-x^-1y)/(x^-1+y^-1)
=(x/y-y/x)/(1/x+1/y)——分子分母同时乘以xy
=(x²-y²)/(y+x)
=(x+y)(x-y)/(y+x)
=x-y
=2-(-1)
=3
(xy^-1-x^-1y)/(x^-1+y^-1)
=(x/y-y/x)/(1/x+1/y)——分子分母同时乘以xy
=(x²-y²)/(y+x)
=(x+y)(x-y)/(y+x)
=x-y
=2-(-1)
=3
看了 化简求值:(xy^-1-x^...的网友还看了以下：
实在太久忘记了.1.f(x)=e^XcosX+ArctanX求f(0)2.x^4-xy+y^4=1求 2020-03-31 …
1.多项式-a(a-x)(x-b)+ab(a-x)(b-x)的公因式是?2.因式分解(a+4)^2 2020-04-08 …
(1-x)y''+xy'-y=-(x-1)^2求通解详细过程 2020-04-26 …
3(x²-y²)-1/2(xy-y)²化简 2020-05-16 …
已知x+y=-2,a+b=-1/2,x^2-xy+y^2=-1,求bx^3+ay^3+by^3+a 2020-05-16 …
已知x、y、z都是正数,x^2+xy+y^2=1,y^2+yz+z^2=3,z^2+zx+x^2= 2020-06-12 …
把几个整式的积化为一个多项式叫什么?y方+xy+y(x+1)叫因式分解那y(x+1)=y方+xy叫 2020-07-13 …
1.下列各式中,形如a^2±2ab+b^2形式的多项式有（）①a^2-a+1/4②x^2+xy+y 2020-07-31 …
证明(x-y)/(1+xy)+(y-z)/(1+yz)+(z-x)/(1+zx)=(x-y)/(1+ 2020-11-01 …
一道好玩的题目1.若X^2-XY=2,XY-Y^2=-1,则X^2-2XY+Y^2的值是多少?2.一 2020-11-04 …