Question

answer this question ​

Answer 1

$a_5+a_9=40 \\ (a+4d)+(a+8d)=40 \\ \implies a+6d=20 \cdots(1) \\ a_8+a_{14}=64 \\ (a+9d)+(a+13d)=64 \\ \implies a+10d=32 \cdots (2) \\ \text{from (1) and (2)} \\ d=3 \\ a= 2 \\ S_{n}=\dfrac{n(2a+(n-1)d)}{2} \\ S_{20}= 610$

Answer 2

Step-by-step explanation:

in the attachment I have given you a brainly verified answer .

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