Question

решите уравнение
-6x^2+19x+7=0

Answer 1

Решение и ответ:

$\displaystyle -6{x^2}+19x+7=0$

$D={b^2}-4ac={19^2}-4\cdot (-6)\cdot 7=529$

$\displaystyle x=\frac{{-b \pm \sqrt D}}{{2a}}=\frac{{-19\pm \sqrt {529} }}{{2\cdot (-6)}}=\frac{{ - 19 \pm 23}}{{-12}}$

$\displaystyle {x_1}=\frac{{-19+23}}{{-12}}=\frac{4}{{-12}}=-\frac{1}{3}$

$\displaystyle {x_2}=\frac{{-19-23}}{{-12}}=\frac{{-42}}{{-12}}=3.5$