Question

Пожалуйста помогите

Answer 1

По теореме Виета:

${x}^{2} + bx + c = 0 \\ x _{1} + x_{2} = - b \\ x _{1} x_{2} = c</p><p>$

1)

${x}^{2} - 5x - 24 = 0 \\ x _{1} + x_{2} = 5 \\ x _{1} x_{2} = - 24\\ x _{1} = - 3 \\ x_{2} = 8$

2)

$- 8 {x}^{2} + 3x = 0 \\ - 8x(x + \frac{3}{8} ) = 0 \\ x _{1} = 0\\ x_{2} = - \frac{3}{8}$

3)

${x}^{2} + 5x - 24 = 0 \\ x _{1} + x_{2} = - 5 \\ x _{1} x_{2} = - 24 \\ x _{1} = - 8 \\ x_{2} = 3$

4)

${x}^{2} - 24x - 11 = 0 \\ d = ( - 24) {}^{2} - 4 \times ( - 11) = \\ 576 + 44 = 620 \\ ( \sqrt{d} = 2 \sqrt{155} ) \\ x _{1} = \frac{24 + 2 \sqrt{155} }{2} = 12 + \sqrt{155} \\ x_{2} = \frac{24 - 2 \sqrt{155} }{2} = 12 - \sqrt{155}$

Ответ: 3)