∫∫(2x+3y)dxdy=∫∫(3x+2y)dxdy
=2.5∫(∫x+y)dxdy
=2.5 ∫ [0,2]dx ∫ [0,2-x](x+y)dy
=2.5 ∫ [0,2][x(2-x)+0.5(x-2)^2]dx
=2.5∫ [0,2][1-0.5x^2]dx
=5/3