I have answer for both question but my friend have different answer. if you can solve this questions I will really appreciate. Thank you.

Let f : D - R where f(x, y) = x - 3ry -y' for every (x, y) E D where D is bounded by the following four line segments, which are parameterized in the counterclockwise direction. S = {(x, y, f (x, y)) : -2