Subtracting polynomials

Which expression gives the area of the triangle shown below

Oscar and julie ashton are celebrating their 15th anniversary by having a reception hall. they have budgeted $4,500 for their reception. if the reception hall charges a $90 cleanup fee plus & 36 per person, find the greatest number of people that they may invite and still stay within their budget.

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180