Question

ax + by - a+ b =0 , bx - ay - a - b = 0

Answer 1

$(ax - a) + (by + b)= 0 \\ a(x - 1) + b(y + 1) = 0 \\ (a + b)(x - 1)(y + 1) = 0 \\ a = - b \\ x = 1 \\ y = - 1$