8/13 - 1/26 =
7/15 - 7/30 =
2/19 - 1/38 =
5/7 - 3/14 =
4/21 - 1/7 =
с полными решениями(показано на 2 фотке)

Ответ:

[tex] \frac{8}{13} - \frac{1}{26} = \frac{16 -1 }{26} = \frac{15}{26} [/tex]

[tex]\frac{7}{15} - \frac{7}{30} = \frac{14 - 7}{30} = \frac{7}{30}[/tex]

[tex]\frac{2}{19} - \frac{1}{38} = \frac{4 - 1}{38} = \frac{3}{38}[/tex]

[tex]\frac{5}{7} - \frac{3}{14} = \frac{10 - 3}{14} = \frac{7}{14} = \frac{1}{2}[/tex]

[tex] \frac{4}{21} - \frac{1}{7} = \frac{4 - 3}{21} = \frac{1}{21} [/tex]

Ответ:

[tex]1) \: \frac{8}{13} - \frac{1}{26} = \frac{ {8}^{(2} }{13} - \frac{ {1}^{(1} }{26} = \frac{8 \times 2 - 1 \times 1}{26} = \frac{16 - 1}{26} = \frac{15}{26} [/tex]

[tex]2) \: \frac{7}{15} - \frac{7}{30} = \frac{ {7}^{(2} }{15} - \frac{ {7}^{(1} }{30} = \frac{7 \times 2 - 7 \times 1}{30} = \frac{14 - 7}{30} = \frac{7}{30} [/tex]

[tex]3) \: \frac{2}{19} - \frac{1}{38} = \frac{ {2}^{(2} }{19} - \frac{ {1}^{(1} }{38} = \frac{2 \times 2 - 1 \times 1}{38} = \frac{4 - 1}{38} = \frac{3}{38} [/tex]

[tex]4) \: \frac{5}{7} - \frac{3}{14} = \frac{ {5}^{(2} }{7} - \frac{ {3}^{(1} }{14} = \frac{5 \times 2 - 3 \times 1}{14} = \frac{10 - 3}{14} = \frac{7}{14} [/tex]

[tex]5) \: \frac{4}{21} - \frac{1}{7} = \frac{ {4}^{(1} }{21} - \frac{ {1}^{(2} }{7} = \frac{4 \times 1 - 1 \times 2}{21} = \frac{4 - 2}{21} = \frac{2}{21} [/tex]