Question

double integral SSxy dA; R is the region bounded by the trapezoid with vertices (1,3) (5,3) (2,1) and (4,1)

Answer 1

we know it's bounded on top by y=3 and bottom by y=1 but don't know how to integrate it

Answer 2

You may have to integrate your function by turning your trapezoid into a piece-wise function. from 1<x<2, 2<x<4, and 4<x<5, where your outer integral is for x from 1 to 5 and inner is for y from 1 to 3.