dkfr.net
当前位置:首页 >> 2x 3y 2 28x 2y 4xy >>

2x 3y 2 28x 2y 4xy

解: 1/x -1/y=2 (y-x)/(xy)=2 y-x=2xy x-y=-2xy (2x-3xy-2y)/(3x+4xy-3y) =[2(x-y)-3xy]/[3(x-y)+4xy] =[2·(-2xy)-3xy]/[3·(-2xy)+4xy] =(-7xy)/(-2xy) =7/2

设y'=p 则代入原方程得 p³-4xyp+8y²=0 ==>x=p²/4y+2y/p.(1) 令f(y,p)=p²/4y+2y/p ∵f'y=-p²/(4y²)+2/p f'p=p/(2y)-2y/p² ∴代入公式 (1-f'y*p)dy-f'p*pdp=0 得 [1+(p²/(4y²)-2/p)p]dy-[p/(2y)-2y/p&...

x3y-4x2y2+4xy3=xy(x2-4xy+4y2)=xy(x-2y)2∵x=2y+1,∴x-2y=1,∴原式=2×12=2.

6a^4b^3-12a^2b^4c =6a^2 * b^3(a^2-2bc) 8m^3n^2-mn^3p=mn^2(8m^2-n*p) 15x^3y^2-10x^2y=5x^2*y(3xy-2) -7a^3b^2-21a^2b^3=-7a^2b^2(a+3b)

解:[(x+2y) 2 ﹣(x﹣2y) 2 ﹣(x+2y)(x﹣3y)﹣6y 2 ]÷(2x)=[x 2 +4xy+4y 2 ﹣(x 2 ﹣4xy+4y 2 )﹣(x 2 ﹣3xy+2xy﹣6y 2 )﹣6y 2 ]÷(2x)=(x 2 +4xy+4y 2 ﹣x 2 +4xy﹣4y 2 ﹣x 2 +3xy﹣2xy+6y 2 ﹣6y 2 )÷(2x)=(9xy﹣x 2 ...

x^2-2xy-y^2+2x+y+2=0,(1) 2x^2-4xy-2y^2+3x+3y+4=0 ,(2) (1)式*2得 2x^2-4xy-2y^2+4x+2y+4=0,(3) (2)式-(3)式得 -x+y=0 x=y 代入(1) y^2-2y^2-y^2+2y+y+2=0 2y^2-3y-2=0 (y-2)(2y+1)=0 y1=2,y2=-1/2 x1=2,x2=-1/2 解是; x1=y1=-1/2,x2=y2=2 两组解

ux+vx=3x²+6xy-3y²-2 uy+vy=3x²-6xy-3y²-2 ∵vx=-uy,vy=ux 所以, ux-uy=3x²+6xy-3y²-2 uy+ux=3x²-6xy-3y²-2 ∴ux=3x²-3y²-2 uy=-6xy ∴u=x³-3xy²-2x+C ∴v=3x²y-y³-2y-C f...

题干不全,不能正常作答

网站首页 | 网站地图
All rights reserved Powered by www.dkfr.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com