Помогите с 28 заданием,пожалуйста

1)
$\frac{a}{b} - 1 = \frac{a}{b} - \frac{b}{b} = \frac{a - b}{b}$
2)
$\frac{8}{ {x}^{2} } - \frac{3}{x} + 2 = \frac{8}{ {x}^{2} } - \frac{3x}{ {x}^{2} } + \frac{2 {x}^{2} }{ {x}^{2} } = \frac{8 - 3x + 2 {x}^{2} }{ {x}^{2} }$
3)
$5 - \frac{4m + 5n}{n} = \frac{5n}{n} - \frac{4m + 5n}{n} = \frac{5n - (4m + 5n)}{n} = \frac{5n - 4m - 5n}{n} = - \frac{4m}{n}$
4)
$\frac{4c + 3}{c - 1} - 3 = \frac{4c + 3}{c - 1} - \frac{3(c - 1)}{c - 1} = \frac{4c + 3 - 3(c - 1)}{c - 1} = \frac{4c + 3 - 3c + 3}{c - 1} = \frac{c + 6}{c - 1}$
5)
$\frac{ {a}^{2} + {b}^{2} }{2a - b} + 2a + b = \frac{ {a}^{2} + {b}^{2} }{2a - b} + \frac{(2a + b)(2a - b)}{2a - b} = \frac{ {a}^{2} + {b}^{2} }{2a - b} + \frac{4 {a}^{2} - {b}^{2} }{2a - b} = \frac{ {a}^{2} + {b}^{2} + 4 {a}^{2} - {b}^{2} }{2a - b} = \frac{5 {a}^{2} }{2a - b}$
6)
$m - \frac{25}{m - 5} - 5 = m - 5 - \frac{25}{m - 5} = \frac{ {(m - 5)}^{2} }{m - 5} - \frac{25}{m - 5} = \frac{ {(m - 5)}^{2} - 25}{m - 5} = \frac{ {m}^{2} - 10m + 25 - 25 }{m - 5} = \frac{ {m}^{2} - 10m}{m - 5}$