[" If "(x^(2)+y^(2)+z^(2)-64)/(xy-yz-2x)=-2" and "x+y=3z," then the value "],[" of "z" is: "]

If (x^(2)+y^(2)+z^(2)-64)/(xy-yz-zx)=-2 and x+y=3z, then the value of z is (a) 2 (b) 3 (c) 4 (d) None of these

If x^(2) + y^(2) + z^(2) - xy- yz - zx = 0 , prove that : x= y = z

If x^(2)+xy+xz=135,y^(2)+yz+xy-135,y^(2)+yz+xy=351 and z^(2)+zx+zy=243 Then the value of x is,(x,y,z>0)

(x-y-z)^(2)-(x^(2)+y^(2)+z^(2))=2(yz-zx-xy)

If x+y -z = 4 and x^(2) + y^(2) + z^(2) = 30 , then find the value of xy- yz- zx