Question

помогите пожалуйста 9 класс надо решить под номерами 23,26,27 дам 50 баллов

Answer 1

Ответ:

$1)3 + 7 {a}^{2} + 10a = 0 \\ 7 {a}^{2} + 10 {a}^{} + 3 = 0 \\ {d}^{} = 100 - 4 \times 3 \times 7 = 100 - 84 = 16 \\ \sqrt{d} = \sqrt{16} = 4 \\ \\ {a}^{} 1 = \frac{ - 10 - 4}{14} = - \frac{14}{14} = - 1 \\ {a}^{} 2 = \frac{ - 10 + 4}{14} = - \frac{6}{14} = - \frac{3}{7}$

$2)6 {t}^{2} + 6 = 13t \\ 6 {t}^{2} - 13 {t}^{} + 6 = 0 \\ {d}^{} = {13}^{2} - 4 \times 6 \times 6 = 169 - 144 = 25 \\ \sqrt{d} = \sqrt{25} = 5 \\ \\ {t}^{} 1 = \frac{13 - 5}{12} = \frac{8}{12} = \frac{2}{3} \\ {t}^{} 2 = \frac{13 + 5}{12} = \frac{18}{12} = \frac{3}{2} = 1.5$

$3)4 {z}^{2} = 3 + 4 {z}^{} \\ 4 {z}^{2} - 4 {z}^{} - 3 = 0 \\ {d}^{ } = 16 - 4 \times 4 \times ( - 3) = 16 + 48 = 64 \\ \sqrt{d} = \sqrt{64} = 8 \\ \\ {z}^{} 1 = \frac{4 - 8}{8} = - \frac{4}{8} = - 0.5 \\ {z}^{} 2 = \frac{4 + 8}{8} = \frac{12}{8} = \frac{3}{2} = 1.5$