so then since (a, b) is the inverse of (x, y) then
(a, b) ⊕ (x, y) = 0
(a + x - 1, b + y +2) = (1, -2)
a + x - 1 = 1
a = -x + 2
b + y + 2 = -2
b = -y - 4
so -v = (-x + 2, -y - 4)
I can check this by doing v⊕(-v) = 0 so
(x, y)⊕(a, b) = 0
(x + a - 1, y + b +2) = (1, -2)
x...