Question

Допоможіть з алгеброю даю 40 БАЛЛ

Answer 1

Завдання 7

$\frac{ \frac{ {(x + 7)}^{2} - 14x}{ {x}^{2} - 49 } }{ \frac{ {x}^{2} + 49}{6x - 42} } = \frac{( {(x + 7)}^{2} - 14x)(6x - 42) }{( {x}^{2} - 49)( {x}^{2} + 49) } = \frac{( {x}^{2} + 14x - 49 - 14x)6(x - 7)}{(x + 7)(x - 7)( {x}^{2} + 49)} = \frac{ ({x}^{2} - 49)6(x - 7)}{(x + 7)(x - 7)( {x}^{2} + 49) } = \frac{1 \times 6 \times 1}{(x + 7) \times 1 \times 1} = \frac{6}{x + 7} = \frac{6}{ - 7.1 + 7} = \frac{6}{ - 0.1} = - 60$

Завдання 8

$\frac{ {a}^{3} + 27 {b}^{3} }{ {(a - b)}^{7} } \div \frac{5 {a}^{2}b + 45 {b}^{3} - 15a {b}^{2} }{ {(b - a)}^{7} } = \frac{( {a}^{3} + 27 {b}^{3} ){(b - a)}^{7} }{ {(a - b)}^{7} (5 {a}^{2} b + 45 {b}^{3} - 15a {b}^{2} )} = \frac{(a + 3b)( {a}^{2} - 3ab + 9 {b}^{2} ) {(b - a)}^{7} }{ {(a - b)}^{7} 5b( {a}^{2} + 9 {b}^{2} - 3ab ) } = \frac{(a + 3b) {(b - a)}^{7} }{5b {(a - b)}^{7} } = - \frac{(a + 3b)( {b - a)}^{7} }{5b {(b - a)}^{7} } = - \frac{a + 3b}{5b}$

$a \div 100 \times 20 = a \times \frac{1}{100} \times 20 = \frac{20a}{100} = \frac{a}{5}$

$- \frac{a + 3b}{5b} = - \frac{ a + 3 \times \frac{a}{5} }{5 \times \frac{a}{5} } = - \frac{a + \frac{3a}{5} }{ \frac{5a}{5} } = - \frac{a + \frac{3a}{5} }{a} = - \frac{ \frac{8a}{5} }{a} = - \frac{8a}{5a} = - \frac{8}{5} = - 1 \frac{3}{5}$