Pattern x: Starts at 0. Rule: Add 3.
 Pattern y: Starts at 0. Rule: Add 6.
 The values of Pattern x and Pattern y are graphed on a coordinate graph. Some of the ordered pairs for this pattern are (0, 0) , (3, 6) , (6, 12) , and (9, 18) .
 Which ordered pair also belongs to this pattern?