Question

giúp mình vs ạ 

Answer 1

\(A=\dfrac{-3}{7}\cdot\dfrac{-1}{9}+\dfrac{7}{-18}\cdot\dfrac{-3}{7}+\dfrac{5}{6}\cdot\dfrac{-3}{7}\)

\(=\dfrac{3}{7}\cdot\dfrac{1}{9}+\dfrac{7}{18}\cdot\dfrac{3}{7}-\dfrac{5}{6}\cdot\dfrac{3}{7}\)

\(=\dfrac{3}{7}\cdot\left(\dfrac{1}{9}+\dfrac{7}{18}-\dfrac{5}{6}\right)\)

\(=\dfrac{3}{7}\cdot\left(\dfrac{2}{18}+\dfrac{7}{18}-\dfrac{15}{18}\right)\)

\(=\dfrac{3}{7}\cdot\dfrac{-6}{18}\)

\(=\dfrac{3}{7}\cdot\dfrac{-1}{3}=-\dfrac{1}{7}\)

Answer 2

ta có:

(-1/9+ 7/18+ 5/6).-3/7 vậy: msc là 18

-1/9= -2/18

7/18 giữ nguyên

5/6= 15/18

nên kết quả là 20/18 rút gọn thành 10/9