At a price of $2.24 per bushel, the supply of a certain grain is 7100 million bushels and the demand is 7900 million bushels. At a price of $2.29 per bushel, the supply is 7500 million bushels and the demand is 7800 million bushels. (A) Find a price-supply equation of the form p = mx + b, where p is the price in dollars and x is the supply in millions of bushels. (B) Find a price-demand equation of the form p = mx + b, where p is the price in dollars and x is the demand in millions of bushels. (C) Find the equilibrium point. (D) Graph the price-supply equation, price-demand equation, and equilibrium point in the same coordinate system. (A) The price-supply equation is p = (Type an exact answer.)