(-3x^3y/9z^2)^2

X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 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 2(x+y)(x+y-z)+3(y-z)(x+y-z) x+y=5 2x+3y-z=9 x-y+z=4 (x-3y+2z)(x+3y-2z) （x-2y+3z)(x+2y-3z) (2y-x-3z)(-x-2y-3z) 三元一次方程x+y+z=0 4x+2y+z=3 9x+3y+z=6x+y+z=04x+2y+z=3 9x+3y+z=6 解方程 x+y+z=0 4x+2y+z=3 9x-3y+z=28解方程x+y+z=04x+2y+z=39x-3y+z=28 2(x+y-z)-3(x-y+z)-5(x+y-z)+6(x-y+z) 计算 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 化简-(-3x-y+2z)-{-x+【4x-(x-y-z)-3x+2z} 2x+y-z=2 x-y+2z=2 3x+2y+4z=9 2x+y-z=2 x-y+2z=2 3x+2y+4z=9 3x+2y+z=9,x+y+2z=0,2x+3y-z=11 x=2y-9z x+2y-3z=2 x-2y+6z=1