Profit Maximizing with Price Discrimination

1. First, set the marginal revenue equal to the marginal cost in each market, which will be equal to the price.
2. If not already done, it is helpful to invert the demand curve so you have price equal to a function.  Then multiply them by quantity again and derive to find the marginal revenues.
3. If the equations are intertwined, then you have to solve for a common marginal cost and set the marginal revenues equal, then solve the system of equations. 

How to Derive Marshallian, Hicksian, and Slutsky Demand Curves