Economics: I'm stuck with this wage differential question. If you wouldn't mind explaining or showing steps I would appreciate it. Thanks!

Let Aw E (wb Lug) denote the wage differential between industries a and b. Suppose that the wage offered by industry a is constant at wa = $8, but that b's wage, wb, is variable. Assume that the supply of labor to industry b is S(Aw) = 10 + 3 - Aw and that b's demand for labor is Daub) = 30 wb. What is the equilibrium compensating wage differential Aw*? Calculate and enter it below. Continuing with the previous question, now suppose that the (constant) wage offered by industry a is wa = $20. What is the equilibrium compensating wage differential Aw* now? Calculate and enter it below