Question

find the sum of the first terms of each of the arithmetic sequence below 21,32,43​

Answer 1

Answer:

: mark me as a brainlist. Step-by-step explanation: 21,32,43.... A=21. D=32-21=11. for 25 th term. a+24d. 21+ 24(11).

3 votes

Answer 2

Step-by-step explanation:

$a = 21 \: l = 43 \\ sum \: of \: the \: first \: 3terms \: = \frac{n}{2}(a + l) \\ = \frac{3}{2} (21 + 43) \\ = \frac{3}{2} \times 64 \\ = 3 \times 32 \\ = 96$