Question

Срочно допоможіть 4,5,6,7 срочно!!!

Answer 1

$4) \frac{ \sqrt{50} }{5} = \sqrt{2}$

$5) \sqrt{21} - \sqrt{3} = \sqrt{3} ( \sqrt{7} - 1)$

$6) ... = \frac{6 {a}^{2} + ac + 36ac + 6 {c}^{2} - ac - 36ac + 6 {c}^{2} }{a} \times \frac{1}{ {a}^{2} + {c}^{2} } = \frac{12a + 12c}{a} \times \frac{1}{ {a}^{2} + {c}^{2} } = \frac{12}{a}$

$7) \frac{1}{x + 4} + \frac{x}{ {x}^{2} + 6x + 8 } = \frac{1}{x + 4} + \frac{x}{(x + 4)(x + 2)} = \frac{2x + 2}{ {x}^{2} + 2x + 4x + 8} = \frac{2x + 2}{x { + 6x + 8}^{2} }$