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

If 3x-4y+z=7; 2x-z+3y=19 ; x+2y+2z=24 , then what is the value of z ? (a) 4 (b) 5 (c) 6 (d) 8

If x^(2) + 3y^(2) + 4z^(2)+ 19 = 4 sqrt(3) ( x + y + z) , then the value of ( x - y + 4z) is:

If x = 2a- 1, y = (2a - 2) and z =3 - 4a, then the value of x ^(3) + y ^(3) + z ^(3) will be :

If x^2 + y^2 + z^2 =2 (x-y-z) - 3, then the value of 2x - 3y + 4z is [Assume that x, y, z are all real numbers] :

The image of plane 2x-y+z=2 in the plane mirror x+2y-z=3 is (a) x+7y-4x+5=0 (b) 3x+4y-5z+9=0( c) 7x-y+2z-9=0 (d) None of these