Remember, an ordered pair, or a point on a graph is written in the form (x,y). Therefore if the problem wants to know what value for x and what value for y satisfies an equation, the first number means x and the second number means y.
Therefore in the problem you are asking about, we have to decide if (2,3) is a solution to the two equations given. So, if x=2 and y=3 all we have to do is plug in the values of x and y and see if they are true or false.
First equation is: x + y = -1 so 2 + 3 = -1 and 5 = -1 is a false statement and therefore says the the ordered pair (2,3) is not a solution to the system. Also remember that for an ordered pair to be a solution to the system, the ordered pair must satisfy both equations. Hope this helps.