please please help me ASAP!!! I'm very stuck and will give brainiest! >:) Find the sum of the first 100 terms of the arithmetic sequence with the first term 2 and the common difference 5.
The arithmetic sequences 1, 5, 9, 13,... and 1, 8, 15, 22,... have infinitely many terms in common. Calculate the sum of the first three common terms.