Here, You have an equation: y = 10x - 20
If you put x = 2, then y = 10(2) - 20 = 20 - 20 = 0
So, Your first point on the graph would be: (2, 0)
Then, for every x value, y will increase for 10 (which is the cost of a ceramic bowl)
So, next coordinates of your graph would be: (3, 10) (4, 20) (5, 30) ( 6, 40) and so on...
Just mark that points, and draw a line on them. Your Graph work will be done.
Hope this helps!