\(15-\frac{15}{7}-\frac{15}{2}=15.\left(1-\frac{1}{7}-\frac{1}{2}\right)=15.\frac{5}{14}=\frac{75}{14}\)
\(8-\frac{3}{7}-\frac{3}{12}=5+3.1-3.\frac{1}{7}-3.\frac{1}{12}=5+3.\left(1-\frac{1}{7}-\frac{1}{12}\right)=5+\frac{65}{28}=\frac{205}{28}\)
15 - 15/7 - 15/2 = 15 - 30/14 - 105/14
= 15 - ( 30/14 - 105/14 )
= 15 - ( -75/14 )
= 210/14 - ( -75/14 )
= 285/14
8 - 3/7 - 3/12 = 8 - ( 36/84 - 21/84 )
= 8 - 15/84
= 672/84 - 15/84
= 657/84
ko đúng thì thôi nha
