There are four different equations possible from this given equation. They are
x+y=2
x-y=2
-x+y=2
-x-y=2
These lines forms a rhombus having diogonal length 4. The area of rhombus is $$\frac{1}{2}\cdot d_1\cdot d_2$$.
$$\frac{1}{2}\cdot4\cdot4\ =\ 8$$