Question

7х в квадрате-5х-2=0 срочно​

Answer 1

$7x^{2}-5x-2=0\\\\D=(-5)^{2}-4\cdot 7\cdot (-2)=25+56=81=9^{2} \\\\x_{1}=\dfrac{5-9}{14} =-\dfrac{4}{14}=-\dfrac{2}{7} \\\\x_{2}=\dfrac{5+9}{14}=\dfrac{14}{14} =1\\\\Otvet:\boxed{-\dfrac{2}{7} \ ; \ 1}$

Answer 2

Ответ:

$- \frac{2}{7} ;1.$

Объяснение:

7х² - 5х - 2 = 0 ;

D = (-5)² - 4 * 7 * (-2) = 25 + 56 = 81 = 9² ;

$x_{1} = \frac{5 - 9}{2 \times 7} = \frac{ - 4}{14} = - \frac{2}{7} ;$

$x_{2} = \frac{5 + 9}{2 \times 7} = \frac{14}{14} = 1.$