Question

Answer 1

\(A=\dfrac{3}{7}\cdot\dfrac{-7}{19}+\dfrac{3}{5}\cdot\dfrac{5}{12}\cdot\dfrac{6}{19}-\dfrac{5}{19}\cdot\dfrac{6}{10}\\ =\dfrac{3}{7}\cdot\dfrac{-7}{19}+\dfrac{3}{5}\cdot\dfrac{5}{19}\cdot\dfrac{6}{12}-\dfrac{5}{19}\cdot\dfrac{6}{10}\\ =\dfrac{3}{7}\cdot\dfrac{-7}{19}+\dfrac{3}{5}\cdot\dfrac{5}{19}\cdot\dfrac{1}{2}-\dfrac{5}{19}\cdot\dfrac{3}{5}\\ =-\dfrac{3}{19}+\dfrac{3}{5}\cdot\left(\dfrac{5}{19}\cdot\dfrac{1}{2}-\dfrac{5}{19}\right)\\ =-\dfrac{3}{19}+\dfrac{3}{5}\cdot\dfrac{5}{19}\cdot\left(\dfrac{1}{2}-1\right)\\ =-\dfrac{3}{19}+\dfrac{3}{19}\cdot\dfrac{-1}{2}=\dfrac{3}{19}\cdot\left(-1+\dfrac{-1}{2}\right)\\ =\dfrac{3}{19}\cdot\dfrac{-3}{2}=-\dfrac{9}{38}\)

Answer 2

\(=\dfrac{-3}{19}+\dfrac{3}{19}\cdot\dfrac{1}{2}-\dfrac{3}{19}\)

=-3/19(-1-1+1/2)

=-3/19*(-3/2)=9/38