John bought 6 dumplings for $3.00. Let x represent the number of dumplings purchased, and let y represent the total cost. Graph the line that represents the proportional relationship.

We know that each dumpling cost $3, and [tex]x[/tex] represents the number of purchased dumplings. So the total cost of some purchased dumplings will be [tex]3x[/tex]. Since we also know that [tex]y[/tex] also represents the total cost, we can equate them to find the equation of our proportional relationship:
[tex]y=3x[/tex]
Now that we have our equation, to graph our line we are going to choose tow values for [tex]x[/tex], then get the values of [tex]y[/tex] for each value of [tex]x[/tex], and then join the tow pair of points using a line:
- If [tex]x=6[/tex], [tex]y=3(6)=18[/tex], so our first pair is (6,18)
- If [tex]x=0[/tex], [tex]y=3(0)=0[/tex], so our second pair is (0,0).