Question

Найдите корни квадратного уравнения:    5х2-4х-12=0​

Answer 1

Ответ:

$5 {x}^{2} - 4 x - 12 = 0 \\ \\ D = { (- 4)}^{2} - 4 \times 5 \times ( - 12) = 16 + 240 = 256 \\ \\ x = \frac{ - ( - 4)± \sqrt{256} }{2 \times 5} = \frac{4±16}{10} \\ \\ x _{1} = \frac{4 + 16}{10} = \frac{20}{10} = 2 \\ \\ x _{2} = \frac{4 - 16}{10} = \frac{ - 12}{10} = - \frac{6}{5}$