6/15+6/35+6/63+6/99+6/143 Question 6/15+6/35+6/63+6/99+6/143 in progress 0 Môn Toán Ladonna 5 years 2021-05-23T19:04:45+00:00 2021-05-23T19:04:45+00:00 2 Answers 47 views 0
Answers ( )
6/15+6/35+6/63+6/99+6/143
=3(2/15+2/35+2/63+2/99+2/143)
=3(2/3.5+2/5.7+2/7.9+2/9.11+2/11.13)
=3(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)
=3(1/3-1/13)
=3.10/39=10/13
6/15+6/35+6/63+6/99+6/143
=6/3.5+6/5.7+6/7.9+6/9.11+6/11.13
=3.(2/3.5+2/5.7+2/7.9+2/9.11+2/11.13)
=3.(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)
=3.10/39
=10/13