If x : y : z = 2:3:4 , then `x/y : y/z : z/x` is equal to

Let x, y, z be non-zero real numbers such that x/y + y/z + z/x = 7 and y/x + z/y + x/z = 9 , then (x^3)/y^3 + y^3/z^3 + z^3/x^3 - 3 is equal to

If x + y = 2z then (x)/(x-z) +(z)/(y-z) = ?

The value of ( x-y ) ( x + y ) + ( y -z ) ( y + z ) + (z-x ) (z + x ) is equal to

If (x + y)/2 = (y+z)/3 = (z + x)/4 , then find x : y: z .