-- pick a small number.
-- write it in the equation in place of x
-- solve the equation for y
-- now you have one x and one y; together they make one point on the graph; take your pencil and make a little dot at that point.
-- pick another small number
-- go through this whole procedure again; then you have another x and y; together they make another point on the graph; mark the new point with your pencil.
-- with your pencil and your ruler, draw a straight line between the two points, and KEEP IT GOING in both directions, as far as you want to.
-- your line will cross the y-axis at 3, and every time it goes 1 box across, it'll go 2 boxes up.
THAT'S the graph of this equation.