一1 .x+z-3=02 .2x-y+2z=23 x-y-z= -3二1.2x+4y+3z=92 3x-2y=5z=113 5x-6y+7z=13三 1.a+b+c=5 2 -4a-2b+c=143.-9a-3b+c=25

{X+y+z=8,X一z=-2,y十z=1 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 解下列方程 三元一次方程一、 5x-3y+z=25x+2y-4z=3-5x+y-z=2二、x+y=-2x+z=13y+z=1三、x-y-z=-13x+5y+7z=114x-y+2z=-1第二题不用了 解方程组 2x一y十3z=3 3x十y一2Z=-1 x十y十Z=5 x+2y-z=0 2x-3z=1 3x-y+2z=4x+2y-z=02x-3z=13x-y+2z=4 x+y+z=6 x+2y+3z=14 y+1=z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y= matlab解对数方程组[x,y,z]=solve('0.29744*x/(3+0.1*x+y+z)=(log10((3+x+y+z)/(3+0.1*x+y+z)))^2','0.79*x/(3+0.1*y+z)=(log10((3+x+y+z)/(3+0.1*x+y+z)*(3+y+z)/(3+0.1*y+z)))^2','1.25*x/(3+0.1*z)=(log10((3+x+y+z)/(3+0.1*x+y+z)*(3+y+z)/(3+0.*1y+z)*(3+z)/ ①：2×一y+3z=3,②:3x+y一2z=-1,③:x+y+z=5; 1.已知x:y:z=4:5:7,求：（一）2x+3y+z/5z； （二）x+y/y+z 非常急, 如果,根号x-3+| y-2 |+z^2=2z-1 求 （x+z)^y x-y-2z=10 y-3z=-4 3x-y+5Z=21 三元一次方求大神x-y-2z=10y-3z=-43x-y+5Z=21 X:y:Z=1:2:7 2X一y+3Z=21 求步子 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0