Question

Giải giúp mình phép tính

1/7+1/91+1/247+1/475+1/755+1/147

Answer 1

1/7 + 1 / 91 + 1/247 + 1/475 + 1/755 + 1/1147

= 1/1.7 + 1/7.13 + 1/13.19 + 1/19.25 + 1/25.31 + 1/31.37

= 1/6. 6/1.7 + 1/6 . 6/7.13 + 1/6 . 6/13.19 + 1/6 . 6/19.25 + 1/6. 25.31 + 1/6. 31.37

= 1/6 ( 6/1.7 + 6/7.13 + 6/13.19 + 6/19.25 + 6/25.31 + 6/31.37 )

= 1/6. ( 1/1 - 1/7 + 1/7 - 1/13 +1/13 - 1/19 + 1/19 - 1/25 + 1/25 - 1/31 + 1/31 - 1/37

= 1/6 . ( 1/1 - 1/37 )

= 1/6. ( 37/37 - 1/37)

= 1/6 . 36/37

= 6 / 37

Chúc bn học tốt!

Answer 2

1/7 + 1 / 91 + 1/247 + 1/475 + 1/755 + 1/1147

= 1/1.7 + 1/7.13 + 1/13.19 + 1/19.25 + 1/25.31 + 1/31.37

= 1/6. 6/1.7 + 1/6 . 6/7.13 + 1/6 . 6/13.19 + 1/6 . 6/19.25 + 1/6. 25.31 + 1/6. 31.37

= 1/6 ( 6/1.7 + 6/7.13 + 6/13.19 + 6/19.25 + 6/25.31 + 6/31.37 )

= 1/6. ( 1/1 - 1/7 + 1/7 - 1/13 +1/13 - 1/19 + 1/19 - 1/25 + 1/25 - 1/31 + 1/31 - 1/37

= 1/6 . ( 1/1 - 1/37 )

= 1/6. ( 37/37 - 1/37)

= 1/6 . 36/37

= 6 / 37