you have to start with you b which in your problem is 5 so put a point at 5 on the y-axis on your graph. then with the M (the fraction numbers) you have to move either up or down depending if there is a negative number. so yours is 1/2 so then you would start at the 5 point and go up 1 and right 2 then you just keep repeating till you get a few points and can make a line then you just do the same thing for the other equation. start at 3 on the y-axis and then go up 3 and right 4 then just keep repeating till you get a few point and can create a line at the end the lines should cross each other like perpendicular lines
