Solving systems of linear equations

A thorough explanation and step by step process would help me greatly. I do not know how to solve this problem.

Club A charges a $200 initial fee, plus $15 a month. Club B charges a $100 initial fee, plus $20 a month. The costs of belonging to the clubs can be compared using the following equations:

Club A: C = 200 + 15m

Club B: C = 100 + 20m

a) Find the point of intersection of the two lines.

b) After how many months are the costs the same?

Any help is appreciated. Thanks.