Question

Answer 1

= -5/7 . (2/11 + 9/11) + 5/7

= -5/7 . 11/11 + 5/7

= -5/7 . 1 + 5/7

= -5/7 + 5/7

= 0

Answer 2

c) Ta có: \(\dfrac{-5}{7}\cdot\dfrac{2}{11}+\dfrac{-5}{7}\cdot\dfrac{9}{11}+\dfrac{5}{7}\)

\(=\dfrac{-5}{7}\cdot\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{5}{7}\)

\(=\dfrac{-5}{7}+\dfrac{5}{7}=0\)