4 | + | 4 | + … + | 4 | = | |
4 x 6 | 6 x 8 | 106 x 108 |
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Các bạn giúp mình nhé!! Đúng 22 giờ là mình phải nộp cho thầy rồi ạ!!!
\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+....+\dfrac{1}{2003.200}\)
\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+....+\dfrac{1}{2003}-\dfrac{1}{200}\)
\(=1-\dfrac{1}{200}\)
\(=\dfrac{199}{200}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
A = \(\dfrac{1}{5}.\dfrac{4}{7}+\dfrac{1}{5}.\dfrac{3}{7}-\dfrac{1}{5}\) A = \(\dfrac{1}{5}.\dfrac{4}{7}+\dfrac{1}{5}.\dfrac{3}{7}-\dfrac{1}{5}.1\) A = \(\dfrac{1}{5}.\left(\dfrac{4}{7}+\dfrac{3}{7}-\dfrac{7}{7}\right)\) A = \(\dfrac{1}{5}.0\) A = \(0\)
C = \(\dfrac{3}{7}.\dfrac{5}{8}+\dfrac{3}{7}.\dfrac{11}{8}-\dfrac{3}{7}\) C = \(\dfrac{3}{7}.\dfrac{5}{8}+\dfrac{3}{7}.\dfrac{11}{8}-\dfrac{3}{7}.1\) C = \(\dfrac{3}{7}.\left(\dfrac{5}{8}+\dfrac{11}{8}-\dfrac{8}{8}\right)\) C = \(\dfrac{3}{7}.1\) C = \(\dfrac{3}{7}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)