Đáp án+Giải thích các bước giải:
$\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{9}{11}.\dfrac{-5}{5}+1\dfrac{5}{7}\\=\dfrac{5}{7}.\dfrac{-2}{11}+\dfrac{9}{11}.(-1)+1+\dfrac{5}{7}\\=\dfrac{5}{7}.\left(\dfrac{-2}{11}+1\right)+\dfrac{9}{11}.(-1)+1\\=\dfrac{5}{7}.\dfrac{9}{11}+\dfrac{9}{11}.(-1)+1\\=\dfrac{9}{11}.\left(\dfrac{5}{7}-1\right)+1\\=\dfrac{9}{11}.\dfrac{-2}7+1\\=\dfrac{-18}{77}+1\\=\dfrac{59}{77}$