Решить уравнение: 1) $x^2 - 16x + 64 = 0$; 2) $81x^2 + 126x + 49 = 0$.
$x^2 - 16x + 64 = 0$ $(x - 8)^2 = 0$ x − 8 = 0 x = 8
$81x^2 + 126x + 49 = 0$ $(9x + 7)^2 = 0$ 9x + 7 = 0 9x = −7 $x = -\frac{7}{9}$
