The solution can be found where two lines intersect. The lines in the image do not intersect at an exact point, so we will need to estimate.
The x value is either 1 or -1 from your choices. You can see it is closer to -1 on the horizontal (x axis).
The y value is either 0 or -1 from your choices. You can see it is closer to 0 on the vertical (y axis).
The answer to your set of lines is approximately (-1,0).
Get x on one side then you can use substitution
So, change x+3y=3 to x= -3y+3
Then plug in x to other equation to find y
2(-3y +3)-3y=-12
-6y + 6 -3y = -12
-9y = -18
Divide both sides by negative nine to find y
y = 2
Then plug in to original equation to find x
x + 3(2) = 3
x + 6 = 3
x = -3
So, y = 2 and x = -3