You have the following equation:
-2x - 2y = 8
In order to find a solution for the previous equation, it is necessary to select a value of x and a value of y which makes the equation consistent.
You can notice that if you choose x = -2 and y = -2 you obtain a consistent equation, as follow:
-2x - 2y = 8
-2(-2) - 2(-2) = 4 + 4 = 8
Hence, a solution to the given equation is the point (-2,-2)