Find the rule which gives the number of matchsticks required to make the following matchstick patterns. Use a variable to write the rule.
a: 2n;b: 3n
(a) From the figure, it can be observed that it will require two matchsticks to make T. Therefore, the pattern is 2n.
(b) From the figure, it can be observed that it will require three matchsticks to make Z. Therefore, the pattern is 3n.