8) \(2:(0{,}8+2\cdot(-3))\)

В скобках: \(0.8+2\cdot(-3)=0.8-6=-5.2=-\dfrac{26}{5}\).

\(2:\left(-\dfrac{26}{5}\right)=-\dfrac{5}{13}\).

Ответ: \(-\dfrac{5}{13}\).