\(\frac{\frac{3}{8}-\frac{3}{10}+\frac{3}{11}+\frac{3}{12}}{\frac{-5}{8}+\frac{5}{10}-\frac{5}{11}-\frac{5}{12}}\)

\(=\frac{3\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{\left(-5\right)\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}\)

\(=-\frac{3}{5}\)

\(\frac{\frac{3}{8}-\frac{3}{10}+\frac{3}{11}+\frac{3}{12}}{\frac{-5}{8}+\frac{5}{10}-\frac{5}{11}-\frac{5}{12}}\)

\(=\frac{3\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{\left(\frac{-5}{8}\right)-\left(\frac{-5}{10}\right)+\left(\frac{-5}{11}\right)+\left(\frac{-5}{12}\right)}\)

\(=\frac{3\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{\left(-5\right).\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}\)

\(=\frac{-3}{5}\)

\(\frac{\frac{2}{8}-\frac{2}{10}+\frac{2}{11}+\frac{2}{12}}{\frac{-5}{8}+\frac{5}{10}-\frac{5}{11}-\frac{5}{12}}\)

\(=\frac{2\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{\frac{-5}{8}+\left(\frac{5}{10}-\frac{5}{11}-\frac{5}{12}\right)}\)

\(=\frac{2\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{\frac{5}{8}-\left(\frac{5}{10}-\frac{5}{11}-\frac{5}{12}\right)}\)

\(=\frac{2\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{\frac{5}{8}-\frac{5}{10}+\frac{5}{11}+\frac{5}{12}}\)

\(=\frac{2\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{5\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}\)

\(=\frac{2}{5}\)

\(\frac{\frac{3}{8}-\frac{3}{10}+\frac{3}{11}+\frac{3}{12}}{\frac{5}{8}-\frac{5}{10}+\frac{5}{11}+\frac{5}{12}}+\frac{\frac{3}{2}+1+\frac{3}{4}}{\frac{5}{2}+\frac{5}{3}+\frac{5}{4}}\)

\(=\frac{3.\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{5.\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}+\frac{3.\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}\right)}{5.\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}\right)}\)

\(=\frac{3}{5}+\frac{3}{5}\)

\(=\frac{6}{5}\)

\(\frac{7}{5}+\frac{7}{8}-\frac{1}{8}\times\frac{10}{8}\)

\(=\frac{7\times8+7\times5}{5\times8}-\frac{10}{8}\)

\(=\frac{7\times13}{5\times8}-\frac{50}{40}\)

\(=\frac{91}{40}-\frac{50}{40}=\frac{41}{40}\)

\(\frac{7}{5}+\frac{7}{8}-\frac{1}{8}\times\frac{10}{8}\)

\(=\frac{7}{5}+\frac{7}{8}-\frac{5}{32}\)

\(=\frac{339}{160}\)

sorry,mik lộn

1/2+2/3+3/4+4/5+5/6+6/7+7/8+8/9+9/10x9/10

=9/10x(1/2+2/3)+(3/4+4/5)+(5/6+6/7)+(7/8+8/9)

=9/10x(1/3+3/5+5/7+7/9)

9/10x(1/3+3/5)+(5/7+7/9)

=9/10x1/5+5/9

9/50+5/9

=10

Bn Long làm đúng rồi bn   nguyễn kim arica cứ làm theo cách đó là được .

Bn nào thấy đúng thì ủng hộ nha .

hình như đề bạn sai thì phải đúng ko biết ngỏ bạn làm

cái chỗ có 2 phân số 9/10 đấy

\(\frac{-8}{10}.\frac{74}{7}+\frac{17}{7}.\frac{-8}{13}+\frac{3}{5}=\frac{-8}{7}.\frac{37}{5}+\frac{-8}{7}.\frac{17}{13}+\frac{3}{5}\)

\(=\frac{-8}{7}.\left(\frac{37}{5}+\frac{17}{13}\right)+\frac{3}{5}=\frac{-8}{7}.\frac{566}{65}+\frac{3}{5}\)

\(=\frac{-4528}{455}+\frac{273}{455}=\frac{-4255}{455}=\frac{851}{91}\)

851/91