Obliczenia :
Liczba odwrotna do a to [tex]\frac{1}{a}[/tex]
[tex]a=-2,25\\\\\frac{1}{a}=\frac{1}{-2,25}=\frac{1}{-2\frac{1}{4}}=\frac{1}{-\frac{9}{4}}=\boxed{-\frac{4}{9}}[/tex]
