Find the sixth and twentieth terms and the sum of the first 10term of each of the following Sequences [ -15,-9,-3, ldots.-9-(-15)=6 ]

To find the sixth and twentieth terms of the sequence, we can use the formula for the nth term of an arithmetic sequence: where is the nth term, is the first term, is the term number, and is the common difference.In this case, the first term is -15, and the common difference is 6 (since the difference between consecutive terms is 6).Let's find the sixth term: So, the sixth term of the sequence is 15.Now, let's find the twentieth term: So, the twentieth term of the sequence is 99.To find the sum of the first 10 terms of the sequence, we can use the formula for the sum of the first n terms of an arithmetic sequence: where is the sum of the first n terms, is the number of terms, is the first term, and is the common difference.In this case, the first term is -15, the common difference is 6, and we want to find the sum of the first 10 terms ( ): So, the sum of the first 10 terms of the sequence is 120.