已知2x-5y＝0，且y不等于0-搜答案-智慧作业帮

∵x2-x=5y2-y=5∴x2-x=y2-yx2-y2=x-y∵x≠y∴x-y≠0x2-y2=x-y左右两边同时除以x-y等于：x+y=1∴x+y-7=-6

令(X+Y)/5=(Y+Z)/6=(x+z)/7=k得x+y=5k①y+z=6k②z+x=7k③以上三式左右分别相加得2(x+y+z)=18kx+y+z=9k④④-②得x=3k④-③得y=2k④-①得

67/78,令3x=4y=5z=60k即可

你的问题可能有错误,如果“求代数式x²-2xy-5y²除x²+2xy=5y²的值”中的“=”为“-”的话解题过程如下：∵x²-xy-2y²=

x+2x-y+6y-8=0x+2x+1-(y-6y+9)=0(x+1)-(y-3)=0(x+1)=(y-3)x+1=±(y-3)x+1=y-3x-y=-4x+1=-(y-3)x+y=2(舍)∴x-y=

5x-4y=0;x=4y/5;x^2+y^2/x^2-y^2-x+y/x-y=（x²+y²-(x+y)²）/(x²-y²)=(x²+y

4x-y+3z=0(1)2x+y+6z=0(2)()+(2)6x+9z=06x=-9zz/x=-2/3(1)*2-(2)8x-2y-2x-y=06x-3y=06x=3yx/y=1/2z/x=-2/3x

简单8x-(2x+y)=8x-2x-y=6x-yx>y6x>y6x-y>0所以8X>2X+y和m没有关系

设X/3=Y/4=Z/5=K,然后表示出X,Y,Z,再代入求解,答案应该是-1/4

因为x+2y-z=0,7x-y-z=0两式相减,得：6x-3y=0,所以y=2x代入x+2y-z=0中,得：x+4x-z=0,那么z=5x那么(x+y+z)÷(2x-y-z)=(x+2x+5x)÷(2

2X+3Y=3X-8Y=5Z解得X=11Z/5,Y=Z/5X+Y\X-Y=11Z/5+1/11-Z/5=2Z+1/11

3x-2y=3y两边同时-y,得3x-3y=4y,左边因式分解得3(x-y)=4y,两边同除以3y,得(x-y)/y=4/3

依题意有f(0+0)+f(0-0)=2f(0)*f(0)又f(0)不等于0所以f(0)=1当x=0,y取任何实数时f(0+y)+f(0-y)=2f(0)*f(y)=2f(y)所以f(-y)=f(y)所

2x²-xy-3y²=0(x+y)(2x-3y)=0x=-y(舍去)或x=3y/2x/y=3/2x/y-x²/(x-y)=x/y-x²/(x²-2xy

无解

4x-5y+2z=0,乘3,12x-15y+6z=0x+4y-3z=0,乘2,2x+8y-6z=0两式相加,14x-7y=02x=yx/y=1/2.

因为,x-y=3xy所以：-3x+6xy+3y/[(7x-5y)-9xy-(3x-y)]=[-3(x-y)+6xy]/[(7x-5y)-9xy-(3x-y)]=[-3*3xy+6xy]/[7x-5y-

首先,若x不等于0,则y也不等于0（因为假如y等于0,代入式子中x也为0与题意不符）,过程如下5x=-8y,5x/y=-8,x/y=-8/5,y/x=-5/8完了.哎!这个问题很简单啊!骚年!要好好学

5x+8y=0化为y/x=-5/8

2x²-xy-3y²=0(x+y)(2x-3y)=0x=-y,2x=3yx≠-y所以y=(2/3)x原式=(x²+2/3*x²)/(2/3*x²-4/