\(\left(\frac{7}{8}-\frac{1}{4}\right).\left(\frac{5}{6}-\frac{3}{4}\right)\)

\(=\left(\frac{7}{8}-\frac{2}{8}\right).\left(\frac{10}{12}-\frac{9}{12}\right)\)

\(=\frac{5}{8}-\frac{1}{12}\)

\(=\frac{15}{24}-\frac{2}{24}\)

\(=\frac{13}{24}\)

Lộn : 

\(\left(\frac{7}{8}-\frac{1}{4}\right).\left(\frac{5}{6}-\frac{3}{4}\right)\)

\(=\left(\frac{7}{8}-\frac{2}{8}\right).\left(\frac{10}{12}-\frac{9}{12}\right)\)

\(=\frac{5}{8}.\frac{1}{12}\)

\(=\frac{5}{96}\)

nhầm nhe đây là vật lý