Polygon abcd has the following vertices: a(−3, 3), b(5, 5), c(5, −4), and d(−3, −4) calculate the area of the polygon.

Check the picture below.

notice, is really just an 8x7 rectangle, with a triangle on top, the triangle has a base of 8, and a height of 2.

so, just get the area of the rectangle and the triangle, recall that A = 1/2 bh for a triangle, and sum them up, and that is the area of the polygon.