please help with these questions. i wrote the given cost function on #3

2. The demand equation between price p and quantity q is linear. Market research shows that 10,100 items are sold when the price is $5.00 and 12, 872 items are sold when the price is $4.50. Find the demand equation between p and q. 3. Find the profit function (p, q) as a function of both p and q. C(q) = 10,000 + 2g 4. Use a Lagrange multiplier to find the number of items they should produce to maximize the profit . (If you keep all your numbers exact, this quantity should be a positive integer.) 5. Also find the corresponding item price and maximum profit, each rounded to the nearest cent