2x+y = -8
5x-y = -6
We get some points on each.
To get some points on
2x+y = -8
We arbitrarily choose x=0
2x+y = -8
2(0)+y = -8
0+y = -8
y = -8
So one point is (0,-8)
We arbitrarily choose y=0
2x+y = -8
2x+0 = -8
2x = -8
x = -4
So one point is (-4,0)
We arbitrarily choose y=6
2x+y = -8
2x+6 = -8
2x = -14
x = -7
So one point is (-7,6)
Let's plot those three points:


------------------
To get some points on
5x-y = -6
We arbitrarily choose x=0
5x-y = -6
5(0)-y = -6
0-y = -6
-y = -6
y = 6
So one point is (0,6)
We arbitrarily choose y=1
5x-y = -6
5x-1 = -6
5x = -5
x = -1
So one point is (-1,1)
We arbitrarily choose x=-3
5x-y = -6
5(-3)-y = -6
-15-y = -6
-y = 9
y = -9
So one point is (-3,-9)
Let's plot those three points:


Now from the point where they cross, we draw one line straight to the
x-axis, and another line straight to the y-axis:
We see that one blue line ends up at -2 on the x-axis, and the other
blue line ends up at -4 on the y-axis, which means the solution is
x=-2 and y=-4. The point where the green and red line intersect is
the point (-2,-4).
Now we check to see if when we substitute -2 for x and -4 for y in
each we come out with a true equation.
Substituting them in
2x+y = -8
2(-2)+(-4) = -8
-4-4 = -8
-8 = -8
That checks.
Substituting them in
5x-y = -6
5(-2)-(-4) = -6
-10+4 = -6
-6 = -6
That also checks. So we know that the solution is
(x,y) = (-2,-4)
Edwin