Question

7x²+9x+2≤0
?!?????? ​

Answer 1

Ответ:

Смотри решение на фото..

Answer 2

$7 {x}^{2} + 9x + 2 \leqslant 0 \\ 7 {x}^{2} +9 x + 2 = 0 \\ a = 7\\ b = 9 \\ c = 2 \\ D = {b}^{2} - 4ac = {9}^{2} - 4 \times 7 \times 2 = 81 - 56 = 25 \\ x_{1} = \frac{ - 9 - 5}{2 \times7 } = - \frac{14}{14} = - 1 \\ x_{2} = \frac{ - 9 + 5}{2 \times 7} = - \frac{4}{14} = - \frac{2}{7} \\ {ax}^{2} + bx + c = a(x - x_{1})(x - x_{2}) \\ 7 {x}^{2} + 9x + 2 = 7(x + 1)(x + \frac{2}{7} ) \\ (x + 1)(x + \frac{2}{7} ) \leqslant 0 \\ + + + [ - 1] - - - [ - \frac{2}{7} ] + + + \\ x \: \epsilon \: [ - 1; \: - \frac{2}{7} ]$