Smog Corporation and Grimy Corporation emit pollution in their production processes. The local ...

Smog Corporation and Grimy Corporation emit pollution in their production processes.  The local government has established a standard for the pollution levels of Smog Corporation and Grimy Corporation of 25,000 units of pollution.  To ensure this level of pollution is achieved efficiently, the government sells permits to the corporations that entitle them to emit a unit of pollution.  Smog Corporation has the following demand function for pollution emission permits:   = 15,000 -  .   Grimy Corporation's demand function for pollution emission permits is:   = 13,000 -  . 
What is the equilibrium price of pollution permits?  If the government makes the standard more stringent and allows only 15,000 units of pollution, what happens to the equilibrium price of pollution permits?