how to solve question 1

Given that F(x, y,z) = xyi +(2yz+x ) j+(2z + y ) k and D is the solid formed by the paraboloid z= x' + y' for which as z sb where a > 0 and b>0. (i) Evaluate V-F dV in terms of a and b, in the simplest form. (14 marks) (ii) Hence, if given that V-F dV =768x and b = 9a, find the value of a +b. (6 marks)