Let D be the triangular region in the xy-plane bounded by the lines
y = x, 3X + y = 4 and X + 3y = 12 (see figure). Using the transformation of coordinates x = (3/8)u - (1/8)v and y =-(1/8)u + (3/8)v, express the integral ∫∫D(24x + 8y )dx dy as an iterated integral in the variables u and v. Do not evaluate the integral.
