Question

срочно 100 баллов СРОЧНО​

Answer 1

3.

$\frac{5a + 25}{ {a}^{2} + 10a + 25 } = \frac{5(a + 5)}{(a + 5) {}^{2} } = \frac{5}{a + 5}$

4.

А)

$\frac{5}{b} + \frac{3b - 2}{ {b}^{2} } = \frac{5b + 3b - 2}{ {b}^{2} } = \frac{8b - 2}{ {b}^{2} }$

Б)

$\frac{x - 4}{x + 7} - \frac{28}{ {x}^{2} - 49} = \frac{x - 4}{x + 7} - \frac{28}{(x - 7)(x + 7)} = \frac{(x - 4)(x - 7) - 28}{(x - 7)(x + 7)} = \\ = \frac{ {x}^{2} - 7x - 4x + 28 - 28}{(x - 7)(x + 7)} = \frac{ {x}^{2} - 11x }{ {x}^{2} - 49}$

В)

$\frac{18 {x}^{5} {y}^{4} }{7 {a}^{3}b } \times \frac{14ab}{27x {}^{4} {y}^{7} } = \frac{2x \times 2}{ {a}^{2} \times 3 {y}^{3} } = \frac{4x}{3 {a}^{2} {y}^{3} }$

Г)

$\frac{5 {ab}^{2} + 10 {a}^{2} b}{ {a}^{2} - 25} \div \frac{4 {a}^{2} - {b}^{2} }{ {a}^{2} + 5a} = \frac{5ab(b +2 a) \times a(a + 5)}{(a - 5)(a + 5)(2a - b)(2a + b)} = \\ = \frac{5 {a}^{2}b }{(a - 5)(2a - b)} = \frac{5 {a}^{2} b}{2 {a}^{2} - ab - 10a + 5b }$