If `2:y=12:30` then what is value of y.

For simultaneous equations in x and y , if D = 30 , D_(x) = -18 , D_(y) = -12 , then what is the value of y ?

If x+y+z=2, xy+yz+zx =-11 and xyz =-12, then what is the value of sqrt(x^3 + y^3 +z^3-2) ?

lf x+y+ z= 6, xyz=-10 and x^2 + y^2 +z^2 = 30 , then what is the value of (x^3 + y^3 + z^3) ?