Ta có: $A = \dfrac{\left(\dfrac{-5}{7} - \dfrac{7}{9} + \dfrac{9}{11} - \dfrac{11}{13}\right) \cdot \left(3 - \dfrac{3}{4}\right)}{\left(\dfrac{10}{21} + \dfrac{14}{27} - \dfrac{6}{11} + \dfrac{22}{39}\right) : \left(2 - \dfrac{2}{3}\right)}$

$A = \dfrac{\left(\dfrac{-5}{7} - \dfrac{7}{9} + \dfrac{9}{11} - \dfrac{11}{13}\right) \cdot \dfrac{9}{4}}{\left(\dfrac{10}{21} + \dfrac{14}{27} - \dfrac{6}{11} + \dfrac{22}{39}\right) : \dfrac{4}{3}}$

$A = \dfrac{\left(\dfrac{-5}{7} - \dfrac{7}{9} + \dfrac{9}{11} - \dfrac{11}{13}\right) \cdot \dfrac{9}{4}}{\left(\dfrac{10}{21} + \dfrac{14}{27} - \dfrac{6}{11} + \dfrac{22}{39}\right) \cdot \dfrac{3}{4}}$

$A = \dfrac{\left(\dfrac{-5}{7} - \dfrac{7}{9} + \dfrac{9}{11} - \dfrac{11}{13}\right) \cdot \dfrac{9}{4}}{-\dfrac{2}{3} \cdot \left(\dfrac{-5}{7} - \dfrac{7}{9} + \dfrac{9}{11} - \dfrac{11}{13}\right) \cdot \dfrac{3}{4}}$

$A = \dfrac{\dfrac{9}{4}}{-\dfrac{2}{3} \cdot \dfrac{3}{4}}$ $A = \dfrac{\dfrac{9}{4}}{-\dfrac{1}{2}}$

$A = \dfrac{9}{4} \cdot (-2)$

$A = \dfrac{-18}{4}$

$A = -4,5$

GV Nguyễn Trần Thành Đạt Giáo viên
Tư duy ra được cái đề cũng làm khó học sinh phết anh ạ

Thật ra, ra Steve Jobs Việt Nam thì khó đoán lắm anh ạ

hihi, biết `x = 14` nhưng lười vẽ hình a ơi