我有3道数学题不会，请大家帮我一下，我将万分感谢！！！
2.Your firm has hiref an economist as a consultant.The ecinimist has estimated that your firm's marginal cost curve is MC=2x,where MC is marginal cost in pounds and x is output.
The economist has also estimated that your firm's marginal revenue curve is MR=30-4x,where MR is marginal revenue in pounds.
He also concludes in his report that when output is zero total cost is $4 and states that marginal cost is the first differential of total cost.
a. Find the equation of total cost.
b. If marginal revenue is defined as the fiest differential of total revebue find the equation of total revenue.
c. Profit, p,in pounds is defined as P=TR-TC,Using differential calculus find the profit maximizing output.
d. If average reveue is total revenue divided by output find the equation of average revenue.
e. Sketch marginal revenue,revenue and marginal cost on the same axes.
The经济学家也估计您的公司的边际收入曲线是MR=30-4x，先生是边际收入以磅。
He在他的报道也认为，当产品零时总成本是$4并且阐明，边际成本是总成本第一个差别。
a.发现总成本的等式。
b. 如果边际收入被定义，当总revebue fiest差别发现总收支的等式。
c.赢利， p，以磅被定义成P=TR-TC，使用微分学发现赢利最大化产品。
d. 如果平均reveue是产品划分的总收支发现平均收支的等式。
e.剪影边际收入、收支和在同样轴的边际成本。
