can you please explain how they transform it from x-2y=u-4v ? I didn't get where they were from.

5. (10 pts) Let D denote the triangle with vertices (0, 0), (1, 2), (2, 1). Use the transformation X T(u, v) = (2u + v, u+20) to calculate JJ, 5x - y dA by making a change of variables (you must calculate the integral in wv coordinates for credit). X = 2utv y = utzv YA ( 1, 2 ) T y= 2X S X - 24 = 0-40 = - 30 (0, 1 ) 2X - y = 42-4 = 3u D 20 ( 2 , 1 ) 7 X V = - X+2x Y = 2X ( 1,0 ) 3 u = 2x-y 3 Det ( DT ) = Det ( 2 1 ) = 2 (2 ) -(1 )1 1- 2 = 3 SS 5 x -ydA = [[ [5 (22+V) -(2+20)|3 dudu D O 1 - u = 3 1 qu + 3 v dvdu = 31 quo+ 2 02 lo on = ? 9 2 3 /1 2)