Matchstick Me Iron?

The given figure gives a matchstick pattern of triangles. As in above, find the general rule that gives the number of matchsticks in terms of the number of triangles.

Find the number of matchsticks used in n^(th) pattern.

Find the rule which gives the number of matchsticks required to make the following matchstick patterns. Use a variable to write the rule. A pattern of letter T as T

Find the rule which gives the number of matchsticks required to make the following matchstick patterns. Use a variable to write the rule. A pattern of letter Z as Z