Ta có: \(\dfrac{1}{3}+\dfrac{3}{4}:x=-3\)
\(\Rightarrow\dfrac{3}{4}:x=\left(-3\right)-\dfrac{1}{3}\)
\(\Rightarrow\dfrac{3}{4}:x=\left(-3\right)+\left(-\dfrac{1}{3}\right)\)
\(\Rightarrow\dfrac{3}{4}:x=\left(-\dfrac{9}{3}\right)+\left(-\dfrac{1}{3}\right)\)
\(\Rightarrow\dfrac{3}{4}:x=-\dfrac{10}{3}\)
\(\Rightarrow x=\dfrac{3}{4}:\left(-\dfrac{10}{3}\right)\)
\(\Rightarrow x=\dfrac{3}{4}.\left(-\dfrac{3}{10}\right)\)
\(\Rightarrow x=\dfrac{-9}{40}\)
Vậy \(x=\dfrac{-9}{40}\)
