Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\Rightarrow x=\left(\frac{33}{5}.\frac{1}{6}-\frac{1}{8}.8+\frac{2}{15}.\frac{3}{100}\right).\frac{11}{4}\)
\(=\left(\frac{11}{10}-1+\frac{1}{250}\right).\frac{11}{4}=\frac{13}{125}.\frac{11}{4}=\frac{143}{500}\)
\(A=\frac{1}{5.9}+\frac{1}{9.13}+\frac{1}{13.17}+........+\frac{1}{100.104}\)
\(=\frac{1}{4}.\left(\frac{4}{5.9}+\frac{4}{9.13}+\frac{4}{13.17}+.......+\frac{4}{100.104}\right)\)
\(=\frac{1}{4}.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+.......+\frac{1}{100}-\frac{1}{104}\right)\)
\(=\frac{1}{4}.\left(\frac{1}{5}-\frac{1}{104}\right)\)
\(=\frac{1}{4}.\frac{99}{520}=\frac{99}{2080}\)
\(\dfrac{3}{4}\times\dfrac{8}{5}:1\dfrac{1}{6}\)
=\(\dfrac{6}{5}:\) \(\dfrac{7}{6}\)
=\(\dfrac{6}{5}\times\dfrac{6}{7}=\dfrac{36}{35}\)
2\(\dfrac{1}{3}\) x 1\(\dfrac{1}{4}\) -\(\dfrac{7}{5}\)
\(\dfrac{7}{3}\times\dfrac{5}{4}-\) \(\dfrac{7}{5}\)
\(\dfrac{35}{12}-\dfrac{7}{5}\)
\(\dfrac{175}{60}-\dfrac{84}{60}=\dfrac{91}{60}\)
4\(\dfrac{2}{3}+1\dfrac{1}{4} +2\dfrac{1}{3}+2\dfrac{3}{7}\)
(4 +2) + \(\left(\dfrac{2}{3}+\dfrac{1}{3}\right)\) +1\(\dfrac{1}{4}\) + \(2\dfrac{3}{7}\)
6 + 1 + \(\dfrac{5}{4}\) + \(\dfrac{17}{7}\)
7 + \(\dfrac{103}{28}\)
\(\dfrac{299}{28}\)
\(\Rightarrow x=\left(\frac{33}{5}.\frac{1}{6}-\frac{1}{8}.8+\frac{2}{15}.\frac{3}{100}\right).\frac{11}{4}\)
\(\Rightarrow x=\left(\frac{11}{10}-1+\frac{1}{250}\right).\frac{11}{4}=\frac{13}{125}.\frac{11}{4}=\frac{143}{500}\)
\(\frac{3}{2\times3}\)+\(\frac{3}{3x4}\)+\(\frac{3}{4x5}\)+ ... +\(\frac{3}{96x97}\)
= \(\frac{3}{2}\)-\(\frac{3}{3}\)+ \(\frac{3}{3}\)- \(\frac{3}{4}\)+\(\frac{3}{4}\)-\(\frac{3}{5}\)+ ... + \(\frac{3}{96}\)- \(\frac{3}{97}\)
ở giữa cứ trù \(\frac{3}{3}\) rồi lại cộng \(\frac{3}{3}\)thì hết nên cụm ở giữa là hết
chỉ còn \(\frac{3}{2}\)-\(\frac{3}{97}\)= \(\frac{285}{194}\)
vậy đáp án câu này là \(\frac{285}{194}\)
/HT\
Đặt \(B=\frac{1}{1.2}+\frac{5}{2.7}+\frac{8}{7.15}+\frac{13}{15.28}+\frac{21}{28.49}+\frac{32}{49.81}\)
\(\Rightarrow B=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{15}+\frac{1}{15}-\frac{1}{28}+\frac{1}{28}-\frac{1}{49}+\frac{1}{49}-\frac{1}{81}\)
\(\Rightarrow B=1-\frac{1}{81}\)
\(\Rightarrow B=\frac{80}{81}\)
4x25x4/15x3/16
=100x12/240
=5