\(=\left(-\dfrac{12}{5}+\dfrac{1}{3}\right):\dfrac{31}{10}+\dfrac{3}{4}:\dfrac{3}{2}\)
\(=-\dfrac{31}{15}\times\dfrac{10}{31}+\dfrac{1}{2}\)
\(=-\dfrac{2}{3}+\dfrac{1}{2}\)
\(=-\dfrac{1}{6}\)
8) \(\left(-2,4+\dfrac{1}{3}\right):3\dfrac{1}{10}+75\%:1\dfrac{1}{2}\)
\(=\left(-\dfrac{12}{5}+\dfrac{1}{3}\right):\dfrac{31}{10}+\dfrac{3}{4}:\dfrac{3}{2}\)
\(=-\dfrac{31}{15}\cdot\dfrac{10}{31}+\dfrac{3}{4}\cdot\dfrac{2}{3}\)
\(=-\dfrac{2}{3}+\dfrac{1}{2}\)
\(=-\dfrac{1}{6}\)