How do you interpret multiple shifts in a supply/demand curve?

Question

I'm trying to figure out how to best interpret multiple shifts in a supply/demand curve. Suppose that a new law requires every firm to provide its workers with free cell phones. The cell phones are worth $200 a year to the works and cost the firms $500 a year to provide. On a labor supply/demand curve, how do I know how much the equilibrium wage goes up or down after the law is enacted?

Answer 1

Supply curve shifts up by $200 at every salary level, but the demand curve shifts down by $500 at every level.  Because the shift in the demand curve is larger than the shift in the supply curve, the real wage falls.