(x y)²减(x-y)²多少等于
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/14 06:58:20
解题思路:本题主要利用完全平方公式进行因式分解即可求出结果解题过程:解:x²-6xy+9y²=(x-3y)2
√xy+y分之一+√xy+x分之一=√xy(1/x+1/y)=√xy乘[(x+y)/xy]=√xy(x+y)再问:√xy(1/x+1/y)这一步怎样计算?再答:(1/x+1/y)1/x和1/y通分再问
6xy²-9x²y-y³=-y(9x²-6xy+y²)=-y(3x-y)²
-2,前提是xy都不为零再问:能说一下解题步骤吗?
xy=x-y两边同时除以xy1=1/y-1/xy分之一减x分之一等于1
解题思路:将原方程右边分解因式为(x-4y)(x+y)=0,可得x=4y或x=-y,进而可求出x与y的比值。解题过程:解:∵x2-3xy-4y2=0∴(x-4y)(x+y)=0∴x=4y或x=-y∵x
x分之1减y分之1等于2(y-x)xy=2y-x=2xyy减xy减x分之3x加xy减3y=[3(x-y)+xy]/(y-x-xy)=(-6xy+xy)/(2xy-xy)=-5xy/xy=-5
令xy=t,则xy/(1-e^xy)=t/(1-e^t),满足洛必塔法则条件,当(x.y)→(0,0)时,limxy/(1-e^xy)=limt/(1-e^t)=lim1/(—e^t)=—1
x²y-xy²=xy(x-y)=3×2=6再问:怎样变为xy(x-y)再答:提取公因式x²y=(xy)×(x)xy²=(xy)×(y)都有因式xy,可以提取出来
[2x(x²y-xy²)+xy(xy-x²)]÷x²y=[2x²y(x-y)+x²y(y-x)]÷x²y=2(x-y)+(y-x)
如果题目是:"x的平方减xy分之y加y的平方减xy分之x",那么就是你的那个答案.y/(x^2-xy)+x/(y^2-xy)=y/[x(x-y)]+x/[y(y-x)]=y^2/[xy(x-y)]-x
2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3(x+y)+2xy=3*(-2)+2*3=0
1/x-1/y=3y-x=3xyx-y=-3xy(5x-xy-5y)/(x-xy-y)=(-15xy-xy)/(-3xy-xy)=4
(x+y)*(x+1)-y(x+y)=(x+y)*(x+1-y)
xy=x-y,因为求1/x-1/y,则x,y不会是0,所以等式两边同时处以xy,xy/xy=(x-y)/xy,1=1/y-1/x,则1/x-1/y=-1
x分之1减y分之1等于31/x-1/y=3(y-x)/xy=3y-x=3xy所以x-xy-y分之5x-xy-5y=(-3xy-xy)分之(-15xy-xy)=-4分之(-16)=4
x^2-3y^2=2xyx^2-2xy-3y^2=0(x-3y)(x+y)=0x=3y或者x=-y当x=3yx+2y=5yx-y=2y所以(x+2y)/(x-y)=5/2当x=-yx+2y=yx-y=
xy/(x+y)=2(x+y)/xy=1/21/x+1/y=1/2(3x-xy+3y)/(-x+3xy-y)=(3/y-1+3/x)/(-1/y+3-1/x)=[3(1/x+1/y)-1]/[(3-(
1/x-1/y=(y-x)/xy=-(x-y)/(x-y)=-1