Evaluating a Double Integral Using a Change of Variables In Exercises 17-22, use the indicated change of variables to evaluate the double integral У(х — у)dA х%3D и — и y u 6 4 (3, 3) (7, 3) 2 x (0,...

I get how to do the problem up until ∫∫[u(u+v-u)]

where did they get [u(u+v-u)]  from? Please explain

Extracted text: Evaluating a Double Integral Using a Change of Variables In Exercises 17-22, use the indicated change of variables to evaluate the double integral У(х — у)dA х%3D и — и y u 6 4 (3, 3) (7, 3) 2 x (0, 0) (4, 0) 6 8


Extracted text: y (x- y)lu (u + v- u)] |; S(x.y) S(u.v) dvdu R ue]- dedu 0 0 3 du 2. =8udu