You need to put these in slope intercept form first. y=mx+b
So solve for y
add 8x to both sides
divide by 2
and 8x to both sides
divide both sides by 2
Now put those two equations into your y= screen. Press the y= button of course on the top left of the calculator.
enter the equations, one on each line.
In this case you will come up with a graph that looks like this:
The solution is where the lines cross. Since these two lines are parallel, (notice that both have a slope of 4x.) they never cross. There is no solution.