Question

решите уровнение 2х^2-13х+21=0

Answer 1

$2 x{}^{2} - 13x + 21 = 0 \\D = ( - 13) {}^{2} - 4 \times 2 \times 21 = 169 - 168 = 1 \\ x = \frac{13 - 1}{4} = 3 \\ x = \frac{13 + 1}{4} = 3.5$
Ответ: 3; 3,5