Kết quả của phép tính \(\dfrac{-3}{4}.31\dfrac{11}{23}-0,75.8\dfrac{12}{23}\) là
\(\dfrac{-69}{4}.\)\(\dfrac{69}{4}.\)\(-30\)\(30\)Hướng dẫn giải:\(\dfrac{-3}{4}.31\dfrac{11}{23}-0,75.8\dfrac{12}{23}\\ =\dfrac{-3}{4}.31\dfrac{11}{23}-\dfrac{3}{4}.8\dfrac{12}{23}\\ =\dfrac{-3}{4}.\Big(31\dfrac{11}{23}+8\dfrac{12}{23}\Big)\\ =\dfrac{-3}{4}.\Big(\dfrac{724}{23}+\dfrac{196}{23}\Big)\\ =\dfrac{-3}{4}.40=-30.\)
