Question

Bài 4 : Tính nhanh
h ) \(\dfrac{3}{5}:\left(\dfrac{-1}{15}-\dfrac{1}{6}\right)+\dfrac{3}{5}:\left(\dfrac{-1}{3}-1\dfrac{1}{15}\right)\)
 

Answer 1

\(=\dfrac{3}{5}:\left(\dfrac{-2-5}{30}\right)+\dfrac{3}{5}:\left(\dfrac{-5}{15}-\dfrac{16}{15}\right)\)

\(=\dfrac{3}{5}\cdot\left(\dfrac{30}{-7}+\dfrac{15}{-21}\right)\)

\(=\dfrac{3}{5}\cdot\left(\dfrac{-90}{21}-\dfrac{15}{21}\right)=\dfrac{3}{5}\cdot\dfrac{-105}{21}=-3\)