Răspuns:
Explicație pas cu pas:
[tex] \frac{20}{63} - \frac{ {}^{7)} 2}{9} = \frac{20 - 14}{63} = \frac{6 {}^{(3} }{63} = \boxed{\frac{2}{21}} \\ [/tex]
20/63- 2/9
amplific 2/9 => 7*2/7*9 = 14/63
20/63-14/63= 6/63 ÷3 => 2/21
