Sau khi rút gọn biểu thức :
\(\left(-\dfrac{5}{13}\right)+\left(-\dfrac{2}{11}\right)+\dfrac{5}{13}+\left(-\dfrac{9}{11}\right)\), ta có kết quả là
\(\dfrac{-38}{143}\).\(\dfrac{7}{11}\).\(-1\).\(\dfrac{-7}{11}\).Hướng dẫn giải: \(\left(-\dfrac{5}{13}\right)+\left(-\dfrac{2}{11}\right)+\dfrac{5}{13}+\left(-\dfrac{9}{11}\right)\)
\(=\left[\left(-\dfrac{5}{13}\right)+\dfrac{5}{13}\right]+\left[\left(-\dfrac{2}{11}\right)+\left(-\dfrac{9}{11}\right)\right]\)
\(=\left[\dfrac{-5+5}{13}\right]+\left[\dfrac{\left(-2\right)+\left(-9\right)}{11}\right]\)
\(=0+\left(-1\right)\)
\(=-1\).
