How to solve this calculus question? ?

An outside supplier has offered to sell talbot similar wheels for $1.25 per wheel. if the wheels are purchased from the outside supplier, $15,000 of annual fixed overhead could be avoided and the facilities now being used could be rented to another company for $45,000 per year. direct labor is a variable cost. if talbot chooses to buy the wheel from the outside supplier, then annual net operating income would: