Explanation:
first u need to pick a random coordinate to substitute the X . example 0
y = 2(0) + 1
y =1 , X= 0
X= 1
y= 2(1) + 1
y= 3, X= 1
then you continue this same process and again until u have at least two points to draw a straight line. it kinda depended if u want to fill the entire graph.