11.
[tex]x = 4\frac{1}{3}-1\frac{1}{4}\cdot\frac{2}{3} = 3\frac{4}{3}-\frac{5}{4}\cdot\frac{2}{3} = 3\frac{4}{3}-\frac{5}{6} = 3\frac{8}{3}-\frac{5}{6} = 3\frac{3}{6} = 3\frac{1}{2}[/tex]
Odp. Szukana liczba to 4.
12.
[tex]a = \frac{\sqrt{25}}{\sqrt{16}} = \frac{5}{4} = 1\frac{1}{4}\\\\b = \sqrt[3]{-8} = -2\\\\c = (\frac{1}{2})^{-3} = 2^{3} = 8\\\\b < a < c[/tex]
13.
[tex]\frac{(5^{7})^{-1}\cdot5^{2}}{(5^{-2})^{4}:5^{0}}=\frac{5^{7\cdot(-1)}\cdot5^{2}}{5^{-2\cdot4}:1} =\frac{5^{-7}\cdot5^{2}}{5^{-8}:1}=\frac{5^{-7+2}}{5^{-8}}=\frac{5^{-5}}{5^{-8}} = 5^{-5-(-8)} = 5^{3} = 125[/tex]
