(X/2)+(Y/3)+(Z/5)≈1.77
x/2=y/3=z/5 x+3y-z/x-3y+z
1.(x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2)
因式分解:25x y^2 z^2 (x+y-z)-30xyz(z-x-y)^2+5x y z^3 (z-x-y)
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
X+Y=Z 2X-3Y+2Z=5 X+3Y-Z=3
(2x-3y+z)-3{x-2【-z+(x-y)】-(3y-5z)}
x+y=z 2x-3y+2z=5 x+2y-z=3
解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3
x+y-z=0 2x-3y+2z=5 x+2y-z=3
解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3