Question

Ребят , помогите пожалуйста ❤
СРОЧНО

Answer 1

4)

$( \sqrt{17} - \sqrt{7} ) \times ( \sqrt{17} + \sqrt{17} ) = \\ = 17 \times - 7 = 10$

5)

${x}^{2} - 8x - 20 = 0 \\ d = ( - 8) ^{2} - 4 \times1 \times ( - 20) = 64 + 80 = 144 = {12}^{2} \\ x1 = \frac{8 + 12}{2} = \frac{20}{2} = 10 \\ x2 = \frac{8 - 12}{2} = \frac{ - 4}{2} = - 2$

6)

$\frac{ {a}^{2}b - 4b^{3} }{3ab^{2} } \times \frac{ {a}^{2}b }{ {a}^{2} - 2ab } = \frac{b \times ( {a}^{2} - 4 {b}^{2})}{3b} \times \frac{a}{a \times (a - 2b)} = \\ = \frac{(a - 2b) \times (a + 2b)}{3} \times \frac{a}{a \times (a - 2b)} = \\ = \frac{a + 2b}{3}$