Пошаговое объяснение:

1.

[tex]\frac{x - 5}{3} - \frac{x - 7}{4} = \frac{4(x - 5)}{3 \times 4} - \frac{3(x - 7)}{3 \times 4} = \frac{4x - 20}{12} - \frac{3x - 21}{12} = \frac{4x - 20 - 3x + 21}{12} = \frac{x + 1}{12} [/tex]

2.

[tex]\frac{x + 5}{6} - \frac{x + 7}{3} = \frac{4(x + 5)}{6 \times 2} - \frac{2(x + 7)}{3 \times 4} = \frac{4x + 20 - 2x - 14}{12} = \frac{2x + 6}{12} = \frac{2(x + 3)}{12} = \frac{x + 3}{6} [/tex]