垄断厂商长期均衡

def solve(____):
    a, b = demand_func
    fc, c, d = cost_func
    q_opt = (____) / (____ * (____))
    p_opt = a - b * q_opt
    profit = (____) * q_opt - fc
    return {"____": round(____), "____": round(____), "____": round(____)}