Odpowiedź:
[tex]1) \: \frac{1}{9} a + \frac{1}{8} b - 1 \frac{1}{3} a - \frac{1}{8} b = \frac{1}{9} a - 1 \frac{3}{9} a = - 1 \frac{2}{9} a[/tex]
[tex]2) \: \frac{2}{3} u + \frac{1}{2} - \frac{1}{6} u - \frac{1}{4 } = \frac{4}{6} u + \frac{2}{4} - \frac{1}{6} u - \frac{1}{4} = \frac{3}{6} u + \frac{1}{4} = \frac{1}{2} u + \frac{1}{4} [/tex]