Answer:
Step-by-step explanation:
Given system is
[tex]\left \{ {{x+y=0} \atop {x-y+2=0}} \right.[/tex]
If we graph, the solution would be the interception point between these two lines, because each linear equation represents a line. The lines are attached.
In the graph, you can observe that the solution is the point (-1,1), that is x = -1 and y = 1.
Now, if we want to solve this system by another method, we can just sum both equations and solve for x
[tex]\left \{ {{x+y=0} \atop {x-y+2=0}} \right.[/tex]
[tex]2x+2=0\\x=\frac{-2}{2}=-1[/tex]
Then, we replace this value in one equation to find the other value
[tex]x+y=0\\-1+y=0\\y=1[/tex]
Therefore, the solution is (-1,1)