Can u please solve

A manufacturer has been selling 1800 television sets a week at $420 each. A market survey indicates that for each $22 rebate offered to a buyer, the number of sets sold will increase by 220 per week. a) Find the demand function p(), where a is the number of the television sets sold per week. P() b) How large rebate should the company offer to a buyer, in order to maximize its revenue? c) If the weekly cost function is 126000 + 140x, how should it set the size of the rebate to maximize its profit