Let me also ask you a question: given X - xy = 8, XY - y = - 9, find the value of X + Y - 2XY

Let me also ask you a question: given X - xy = 8, XY - y = - 9, find the value of X + Y - 2XY

x-xy=8 ---- ①
xy-y=-9 ----- ②
You can get it by subtracting (1) from (2)