已知(x+y)÷3=6,(x+z)÷5=6,(y+z)÷2=12.x·y·z的值各是多少?
已知x::y:z=3:4:5,(1)求x+y分之z的值;(2)若x+y+z=6,求x,y,z.
已知方程组{4x-3y-6z=0 x+2y-7z=0 且z≠0,则(x+y+3z)÷(4x-y-5z)=?结果和思路!
已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/(除以)x-y+z的值.
已知4x-3y-6z=0 ① ,x+2y-7z=0 ②,且x,y,z均不为0,求3x+2y+z÷x+2y+3z的值
已知方程组4x-3y-6z=0,x+2y-7z=0(z≠0),求x+y+3z/4x-y-5z的值
已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值
已知x/4=y/5=z/6,求x+y+z/3x-2y+z的值.
已知x、y、z满足方程组:x+y-z=6;y+z-x=2;z+x-y=0 求x、y、z的值
已知3x=4Y,5Y=6Z,求 (1)x:y:z;(2)x+y/y+z.
若x-y=6,xy=-8,求代数式(x+y+z)²+(x-y-z)(x-y+z)-2·z(x+y)的值
已知3/x+y=4/x+y=5/y+z,求xyz/(x+y)(y+z)(z+x)的值
已知|x+(-2)|+|y+3|+|z|=0,求x+y+z的值.