Giá trị biểu thức \(P=\left(\dfrac{-3}{4}+\dfrac{2}{5}\right):\dfrac{3}{7}+\left(\dfrac{3}{5}+\dfrac{-1}{4}\right):\dfrac{3}{7}\) là
\(0.\)\(1.\)\(2.\)\(3.\)Hướng dẫn giải:\(P=\left(\dfrac{-3}{4}+\dfrac{2}{5}\right):\dfrac{3}{7}+\left(\dfrac{3}{5}+\dfrac{-1}{4}\right):\dfrac{3}{7}\)
\(=\left(\dfrac{-3}{4}+\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{-1}{4}\right):\dfrac{3}{7}\)
\(=\left[\left(\dfrac{-3}{4}+\dfrac{-1}{4}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)\right]:\dfrac{3}{7}\)
\(=\left(-1+1\right):\dfrac{3}{7}\)
\(=0:\dfrac{3}{7}=0.\)
