Question 354201
Where the line crosses the x axis, x = 0 and where it crossed the y axis y = 0
so solve each equation using first x = 0 then again with y = 0,.

x-y = 3  if x = 0
0-y = 3
-y = 3
y = -3  so the x intercept is (0, -3)

x-y = 3  if y = 0
x - 0 = 3
x = 3 so the y intercept is (3, 0)  
Now graph each point and connect them with a line..you only need two points to graph a linear system.

Do the same to the other two equations

Hope this helps