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.

This is an arithmetic sequence because each term is 7 greater than the previous term, so 7 is what is called the common difference...

Any arithmetic sequence can be expressed as:

a(n)=a+d(n-1), a=first term, d=common difference, n=term number.

We know a=1 and d=7 so:

a(n)=1+7(n-1)

a(n)=1+7n-7

a(n)=7n-6 

The above is the "rule" for the nth term.

Step-by-step explanation:

1. 8

2. 9

3. 20

4. 3

5. 17

6. 2.2

7. 11.25

8. 1

9. 14

10. 2

step-by-step explanation:

thats the first half