Question

Tính nhanh :

\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.11}+\frac{3}{11.14}+\frac{3}{14.17}.\)

Lưu ý nếu ai nghĩ là sai đề thì không phải như vậy .

Answer 1

mk đi thi hsg mk bik chắc chắn mk ko sai đâu k mk nhé
3/1.4 +3/4.7+....+3/14.17
=1/1-1/4+1/4-1/7+...+1/14-1/17
=1-1/17
=16/17

Answer 2

\(\frac{3}{1}-\frac{3}{4}+\frac{3}{4}-\frac{3}{7}+...\)\(\frac{3}{14}-\frac{3}{17}\)

\(\frac{3}{1}-\frac{3}{17}\)

= \(\frac{18}{7}\)

Answer 3

\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.11}+\frac{3}{11.14}+\frac{3}{14.17}\)

\(=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{17}\)

\(=1-\frac{1}{17}\)

\(=\frac{16}{17}\)

Answer 4

=3-3/4+3/4-3/7+3/7-3/11+3/11-3/14+3/14-3/17

=3-3/17

=51/17-3/17

=48/17

nếu đúng k cho mk nha

Answer 5

\(\frac{1}{7}-\frac{1}{11}\)mà bằng \(\frac{3}{7.11}\)

à .