Question

7x^2-5x-2 Розкладіть на множники квадратний тричлен

Answer 1

$7 {x}^{2} - 5x - 2 = 0 \\ D = ( - 5) {}^{2} - 4 \times 7 \times ( - 2) = 25 + 56 = 81 \: (9) \\ x_{1} = \frac{5 + 9}{14} = \frac{14}{14} = 1 \\ x_{2} = \frac{5 - 9}{14} = - \frac{4}{14} = - \frac{2}{7} \\ \\ 7 {x}^{2} - 5x - 2 = 7(x + \frac{2}{7} )(x - 1) = (7x + 2)(x - 1)$