Arithmetic sequences & series

Given the arithmetic sequence: 8; 14; 20; … Determine $(a)T_{12}$, and $(b)S_{12}$, the sum of the first 12 terms.

Given the arithmetic sequence: 6; 12; 18; … Determine $(a)T_{20}$, and $(b)S_{20}$, the sum of the first 20 terms.

Given the arithmetic sequence: 8; 17; 26; … Determine $(a)T_{20}$, and $(b)S_{20}$, the sum of the first 20 terms.

Given the arithmetic sequence: 4; 8; 12; … Determine $(a)T_{15}$, and $(b)S_{15}$, the sum of the first 15 terms.

Given the arithmetic sequence: 11; 8; 5; … Determine $(a)T_{15}$, and $(b)S_{15}$, the sum of the first 15 terms.

Given the arithmetic sequence: 2; −3; −8; … Determine $(a)T_{12}$, and $(b)S_{12}$, the sum of the first 12 terms.

Given the arithmetic sequence: 11; 6; 1; … Determine $(a)T_{20}$, and $(b)S_{20}$, the sum of the first 20 terms.

Given the arithmetic sequence: 6; 3; 0; … Determine $(a)T_{15}$, and $(b)S_{15}$, the sum of the first 15 terms.

Given the arithmetic sequence: 6; 14; 22; … Determine $(a)T_{15}$, and $(b)S_{15}$, the sum of the first 15 terms.

Given the arithmetic sequence: 3; 1; −1; … Determine $(a)T_{15}$, and $(b)S_{15}$, the sum of the first 15 terms.

Given the arithmetic sequence: 2; −1; −4; … Determine $(a)T_{15}$, and $(b)S_{15}$, the sum of the first 15 terms.

Given the arithmetic sequence: 6; 2; −2; … Determine $(a)T_{12}$, and $(b)S_{12}$, the sum of the first 12 terms.