Question

\(\dfrac{5}{11}\) x \(-\dfrac{3}{7}\) + \(\dfrac{5}{11}\) x \(-\dfrac{5}{11}\) + \(-\dfrac{8}{7}\) x \(\dfrac{6}{11}\)

Answer 1

Ta có: \(\frac{5}{11}\cdot\frac{-3}{7}+\frac{5}{11}\cdot\frac{-5}{11}+\frac{-8}{7}\cdot\frac{6}{11}\)

\(=\frac{-15}{77}+\frac{-48}{77}-\frac{25}{121}\)

\(=-\frac{63}{77}-\frac{25}{121}=\frac{-9}{11}-\frac{25}{121}=\frac{-99}{121}-\frac{25}{121}=-\frac{124}{121}\)