Question

Решите уравнения как можно быстрее.

Answer 1

$24 {x}^{2} = 0 = > x = 0$
$16 {x}^{2} + 9 = 0 \ 16 {x}^{2} = - 9$
корней нет.
$81 {x}^{2} - 144x = 0 \ 9x(x - 16) = 0 \ x = 0 \ x = frac{16}{9}$
$4 {x}^{2} - 52x + 169 = 0 \ {(2x - 13)}^{2} = 0 \ 2x - 13 = 0 \ 2x = 13 \ x = 13 div 2$
$21 {x}^{2} + 14x + 7 = 0 \d = 196 - 588 < 0 = >$
корней нет.
$3 {(x + 2)}^{2} - 63 = 13x - 30 + {x}^{2} \ 3( {x}^{2} + 4x + 4) - 63 - 13x + 30 - {x}^{2} = 0 \ 3 {x}^{2} + 12x + 12 - 63 - 13x + 30 - {x}^{2} = 0 \ 2 {x}^{2} - x - 21 = 0 \ x = frac{1 pm sqrt{1 + 168} }{4} \ x = frac{1 pm13}{4} \ x = - 3 \ x = frac{7}{2}$