Question 106650
I am not sure how to graph a vertical line. But the one line will be as I have graphed, that is for {{{x-2y>=4}}}. It will be a solid line, and the area under the line is shaded. The other line is a vertical line running thru x=4, it also is a solid line and shaded to the left of the line.
Hope you understand
:) 
{{{graph (300,300, -5,5,-5,5, (1/2)x-2)}}}