Answer 1

A = 3/10 + 3/90 + 3/234 + ... + 3/1050

2A = 3/5 + 3/45 + 3/117 + ... + 3/525

2A = 3/1.5 + 3/5.9 + 3/9.13 + ... + 3/21.25

4/3.2A = 4/1.5 + 4/5.9 + 4/9.13 + ... + 4/21.25

8/3.A = 1 - 1/5 + 1/5 - 1/9 + 1/9 - 1/13 + ... + 1/21 - 1/25

8/3.A = 1 - 1/25

8/3.A = 24/25

A = 24/25 : 8/3

A = 24/25 . 3/8 

A = 9/25

Hi hi mk ủng hộ bn rùi đó nhoa

Answer 2

Hic, chán wa đê, ko ai lm, z mk lm

A = 3/10 + 3/90 + 3/234 + ... + 3/1050

2A = 3/5 + 3/45 + 3/117 + ... + 3/525

2A = 3/1.5 + 3/5.9 + 3/9.13 + ... + 3/21.25

4/3.2A = 4/1.5 + 4/5.9 + 4/9.13 + ... + 4/21.25

8/3.A = 1 - 1/5 + 1/5 - 1/9 + 1/9 - 1/13 + ... + 1/21 - 1/25

8/3.A = 1 - 1/25

8/3.A = 24/25

A = 24/25 : 8/3

A = 24/25 . 3/8

A = 9/25

Vì bài này mk ra nên ai mún Ủng hộ thì cứ tự nhin, ko thì thui ng mk vẫn mog m.n

Ủng hộ mk nha ★_★^_-