If `x=1, y=2, z=-1` then find the value of `z^2-2xy(x-y)`

If x = 6, y = 4 and z = 3, then find the value of x ^(2) + y ^(2) + z ^(2) - 2xy + 2 yz - 2 zx.

If x = 2, y = 3 and z = -1, find the values of : (xy)/(z)

If X:Y=3:4,Y:Z=5:2 then find the value of X:Y:Z.

If cos^(-1)x+cos^(-1)y+cos^(-1)z=pi, where -1<=x,y,z<=1, then find the value of x^(2)+y^(2)+z^(2)+2xyz

If x = 1, y = - 2 and z = 3. find the value of (i) x^(3) + y^(3) + z^3-3xyz (ii) 3xy^(4) - 15 x^(2) y + 4z

If x^2+y^2+z^2= xy+yz+zx then find the value of (x+y):z.

If x:y=2:3 , y:z=3:4 , z:k=1:2 , find the value of x:y:z:k

If ( x +y+z ) = 9 and ( xy + yz + zx ) = 26 then find the value of x^(2) + y^(2) z^(2)

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