Mình làm như thế này nek

\(\frac{\frac{1}{4}+\frac{3}{7}-\frac{4}{5}}{0,75+\frac{9}{7}-2\frac{2}{5}}+\frac{\frac{3}{14}-\frac{2}{10}+\frac{5}{18}+\frac{7}{66}}{\frac{6}{7}-\frac{4}{5}+\frac{10}{9}+\frac{14}{33}}\)

\(=\frac{\frac{1}{4}+\frac{3}{7}-\frac{4}{5}}{\frac{2}{4}+\frac{9}{7}-\frac{12}{5}}+\frac{\frac{1}{2}\cdot\left(\frac{3}{7}-\frac{2}{5}+\frac{5}{9}+\frac{7}{33}\right)}{2\cdot\left(\frac{3}{7}-\frac{2}{5}+\frac{5}{9}+\frac{7}{33}\right)}\)

\(=\frac{\frac{1}{4}+\frac{3}{7}-\frac{4}{5}}{3\cdot\left(\frac{1}{4}+\frac{3}{7}-\frac{4}{5}\right)}+\frac{\frac{1}{2}}{2}\)

\(=\frac{1}{3}+\frac{1}{4}=\frac{7}{12}\)

mh biết làm bài này rùi bn có cần mi2h đang cho bn ko?

\(14:\left(4\frac{1}{2}-2\frac{5}{8}\right)+14.\frac{1}{4}.\frac{2}{3}\)

\(=14:\frac{15}{8}+14.\frac{1}{6}\)

\(=14.\frac{8}{15}+14.\frac{1}{6}\)

\(=14.\left(\frac{8}{15}+\frac{1}{6}\right)\)

\(=14.\frac{7}{10}\)

\(=\frac{98}{10}\)

đúng thì ủng hộ nha

\(14\div\left(4\frac{1}{2}-2\frac{5}{8}\right)+14\times\frac{1}{4}\times\frac{2}{3}=14\div\left(\frac{9}{2}-\frac{21}{8}\right)+14\times\frac{1}{4}\times\frac{2}{3}\)

                                                                             \(=14\div\frac{15}{8}+14\times\frac{1}{4}\times\frac{2}{3}\)

                                                                             \(=\frac{112}{15}+\frac{7}{3}\)

                                                                             \(=\frac{49}{5}\)

CHÚC BẠN HỌC TỐT

b)=1/5.(1/4-1/9+1/9-1/14+1/14-1/19+...+1/44-1/49).2-1-3-5-7-...-49/89

=1/5.(1/4-1/49).2-(1+3+5+7...+49)/89

=1/5.45/196.2-625/89

=9/196.-623/89

=9/196.-7

=9/28

h cho mình nha ! Chúc bạn học tốt

\(a,\frac{27^4\cdot2^3-3^{10}\cdot4^3}{6^4\cdot9^3}=\frac{3^{12}\cdot2^3-3^{10}\cdot2^6}{2^3\cdot3^4\cdot3^6}=\frac{3^{10}\cdot2^3\cdot\left(3^2-2^3\right)}{2^3\cdot3^{10}}=3^2-2^3=1\)

\(b,\left(\frac{1}{4\cdot9}+\frac{1}{9\cdot14}+\frac{1}{14\cdot19}+...+\frac{1}{44\cdot49}\right)\cdot\frac{1-3-5-7-...-49}{89}\)

\(=\frac{1}{5}\left(\frac{5}{4\cdot9}+\frac{5}{9\cdot14}+\frac{5}{14\cdot19}+...+\frac{1}{44\cdot49}\right)\cdot\frac{1-\left(3+5+7+...+49\right)}{89}\)

\(=\frac{1}{5}\left(\frac{1}{4}-\frac{1}{9}+\frac{1}{9}-\frac{1}{14}+\frac{1}{14}-\frac{1}{19}+...+\frac{1}{44}-\frac{1}{49}\right)\cdot\frac{1-\left(3+49\right)\cdot24\div2}{89}\)

\(=\frac{1}{5}\left(\frac{1}{4}-\frac{1}{49}\right)\cdot\frac{505}{89}\)

\(=\frac{1}{5}\cdot\frac{45}{196}\cdot\frac{505}{89}\)

cả út sai rồi