Question 113307
To graph an equation of a straight line, you only need to determine two points.  Pick a value for x and then solve for y to give a point on the line.  Do this twice for each line.   Once you have your two points determined, plot them and connect the dots with a straight line.


I'll do the first one:


{{{x-2y=8}}}.  I pick the value 4 for x first.
{{{4-2y=8}}}
{{{-2y=4}}}
{{{y=-2}}}   So now we know that one point is (4, -2).  We'll call that point A


{{{x-2y=8}}}.  I pick the value 0 for x next.
{{{0-2y=8}}}
{{{y=-4}}}   So our other point is (0, -4).  We'll call that point B


I'll leave you to figure two points for the second equation, but I'll show a graph of both lines so that we can see where the simultaneous solution point occurs.


{{{drawing (400,400, -7,7,-7,7,
           grid(1),
locate(.2, -4.2, A( 0, -4 ) ),
locate(4.2, -2.2, B( 4, -2 ) ),
           green(line(-10,-9,10,1)),
           blue(line(10,-11,-10,9)),
           red(circle(0,-4,0.2)),
           red(circle(4,-2,.2))

)}}}


It looks like the lines intersect at (2, -3).


Let's check:

{{{2-2(-3)=2+6=8}}}, so the point is on one of the lines.
{{{2+(-3)=-1}}}, so the point is on the other line as well and the answer checks.