$3x^2 - 14x + 16 = 0$
$D = 7^2 - 3 * 16 = 49 - 48 = 1$
$x = \frac{7 ± \sqrt{1}}{3}$
$x_1 = \frac{7 - 1}{3} = \frac{6}{3} = 2$
$x_2 = \frac{7 + 1}{3} = \frac{8}{3} = 2\frac{2}{3}$
Ответ:
$x_1 = 2$;
$x_2 = 2\frac{2}{3}$.

$5x^2 - 16x + 3 = 0$
$D = 8^2 - 5 * 3 = 64 - 15 = 49$
$x = \frac{8 ± \sqrt{49}}{5}$
$x_1 = \frac{8 - 7}{5} = \frac{1}{5} = 0,2$
$x_2 = \frac{8 + 7}{5} = \frac{15}{5} = 3$
Ответ:
$x_1 = 0,2$;
$x_2 = 3$.

$x^2 + 2x - 80 = 0$
$D = 1^2 - 1 * (-80) = 1 + 81 = 81$
$x = \frac{-1 ± \sqrt{81}}{1}$
$x_1 = \frac{-1 - 9}{1} = -10$
$x_2 = \frac{-1 + 9}{1} = 8$
Ответ:
$x_1 = -10$;
$x_2 = 8$.

$x^2 - 22x - 23 = 0$
$D = 11^2 - 1 * (-23) = 121 + 24 = 144$
$x = \frac{11 ± \sqrt{144}}{3}$
$x_1 = \frac{11 + 12}{1} = 23$
$x_2 = \frac{11 - 12}{1} = -1$
Ответ:
$x_1 = 23$;
$x_2 = -1$.

$4x^2 - 36x + 77 = 0$
$D = 18^2 - 4 * 77 = 324 - 308 = 16$
$x = \frac{18 ± \sqrt{16}}{4}$
$x_1 = \frac{18 - 4}{4} = \frac{14}{4} = 3,5$
$x_2 = \frac{18 + 4}{4} = \frac{22}{4} = 5,5$
Ответ:
$x_1 = 3,5$;
$x_2 = 5,5$.

$15y^2 - 22y - 37 = 0$
$D = 11^2 - 15 * (-37) = 121 + 555 = 676$
$y = \frac{11 ± \sqrt{676}}{15}$
$y_1 = \frac{11 - 26}{15} = \frac{-15}{15} = -1$
$y_2 = \frac{11 + 26}{15} = \frac{37}{15} = 2\frac{7}{15}$
Ответ:
$y_1 = -1$;
$y_2 = 2\frac{7}{15}$.

$7z^2 - 20z + 14 = 0$
$D = 10^2 - 7 * 14 = 100 - 98 = 2$
$z = \frac{10 ± \sqrt{2}}{7}$

$y^2 - 10y - 25 = 0$
$D = 5^2 - 1 * (-25) = 25 + 25 = 50$
$y = \frac{5 ± \sqrt{50}}{1} = 5 ± 5\sqrt{2}$