Question

If a1 a2 a3 a4 a5 a6 a7 are in



a.P and if a4 is 10 then a1+a7 with answer

Answer 1

     

$a_1+a_7 \ = \ a_2+a_6 \ = \ a_3+a_5 \ = \ a_4 + a_4 \ = \ 2 \times a_4 \ = \ 2 \times 10 \ = \ \bold{20}$

$OR$

$a_1+a_7 \\ \\ a_1+a_1+6d \\ \\ 2a_1+6d \\ \\ 2(a_1+3d) \\ \\ 2 \times a_4 \\ \\ 2 \times 10 \\ \\ \bold{20}$

Plz mark it as the brainliest if this helps.

Thank you. :-))

     

Answer 2

a1+a7=a+a+6d

a4=a+3d

10-3d=a

2(10-3d)+6d

20-6d+6d

20