x+y=65 x+z=80 y+z=105 求出x y z所代表的数

(x+y-z)(x-y+z)= X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) (x+y+z)÷10=x+1.1 y+x=z-80+y-1 z-y=8x+y+8 x+z÷y=? 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 解方程组：{x(x+y+z)=6 {y(x+y+z)=9 {z(x+y+z)=10 x+y=8 y+z=12 x+z=10 x+y+z= x+y=8 y+z=12 x+z=10 x+y+z= x+y+z=15 x+5y+10z=70 x,y,z,各是几? x+y+z=15 x+5y+10z=70 x,y,z,各是几? X+Y-Z=15 X+5Y+10Z=70 求：X、Y、Z fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 z+=x>y?++x: 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证? x=y; y=z; z=x/y 若X/10=Y/8=Z/9则X+Y+Z/Y+Z=? X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z