Question

Решить квадратные уравнения 8 класс. Алгебра

Answer 1

Сделала только 3, ибо остальное чутка лень делать) прости

Answer 2

$1) {3x}^{2} + 8x - 3 = 0 \\ d = 64 + 4 \times 3 \times3 = 64 + 36 = \\ 100 = 10$
$x1 = \frac{ - 8 + 10}{6} = \frac{2}{6} = \frac{1}{3} \\ x2 = \frac{ - 8 - 10}{6} = - \frac{18}{6} = - 3$
2)
${5x}^{2} - 8x + 3 = 0 \\ d = 64 - 4 \times 5 \times 3 = 64 - 60 = \\ 4 = 2$
$x1 = \frac{ 8 + 2}{10} = \frac{10}{10} = 1 \\ x2 = \frac{8 - 2}{10} = \frac{6}{10} = 0.6$
3)
$- {x}^{2} - 2x + 15 = 0 | \times ( - 1) \\ {x}^{2} + 2x - 15 = 0 \\ d = 4 + 60 = 64 = 8$
$x1 = \frac{ - 2 + 8}{2} = \frac{6}{2} = 3 \\ x2 = \frac{ - 2 - 8}{2} = - \frac{10}{2} = - 5$
4)
${3x}^{2} + 9 - 12x + {x}^{2} = 0 \\ 4 {x}^{2} - 12x + 9 = 0 \\ d = 144 - 144 = 0$
$x1 = \frac{12 + 0}{8} = \frac{12}{8} = 1 \frac{1}{2} \\ x2 = \frac{12 - 0}{8} = \frac{12}{8} = 1 \frac{4}{8} = 1 \frac{1}{2}$
5)
${2x}^{2} - 3x - 4x + 3 = 0 \\ 2 {x}^{2} - 7x + 3 = 0 \\ d = 49 - 24 = 25 = 5$
$x1 = \frac{3 + 5}{4} = \frac{8}{4} = 2 \\ x2 = \frac{3 - 5}{4} = - \frac{2}{4} = - 0.5$
$6) {x}^{2} - 4x + 3 = 0 \\ d = 16 - 12 = 4 = 2$
$x1 = \frac{4 + 2}{2} = \frac{6}{2} = 3 \\ x2 = \frac{4 - 2}{2} = \frac{2}{2} = 1$
$7)9 {x}^{2} = 2(6x - 2) \\ 9 {x}^{2} - 12x + 4 = 0 \\ d = 144 - 144 = 0$
$x1 = \frac{12}{18} = \frac{4}{6} \\ x2 = \frac{12}{18} = \frac{4}{6}$
Остальное сам до решаешь они все похожие