PLEASE HELP!

When a mutual fund company charges a fee of 0.49% on its index funds, its assets in the fund are $30 billion. When it charges a fee of 0.13%, its assets in the fund are $269 billion. (a) Let x denote the fee that the company charges as a percentage of the index fund and let A(x) denote its assets in the fund. Express A(x) as a linear function of x. (b) One company lowers its fees on various index funds from an average of 0.38% to 0.24%. Let R(x) denote the revenue of the company from fees when its index-fund fee is x%. Compare the revenue of the company before and after lowering the fees. [Hint: Revenue is x% of the assets.] (c) Find the fee that maximizes the revenue of the company and determine the maximum revenue