$\frac{x(x - 3)}{6} - \frac{x}{2} = 0$ |*6
x(x − 3) − 3x = 0
$x^2 - 3x - 3x = 0$
$x^2 - 6x = 0$
x(x − 6) = 0
x = 0 или x − 6 = 0
x = 6
Ответ:
$x_1 = 0$;
$x_2 = 6$.

$\frac{x(x + 1)}{3} + \frac{8 + x}{4} = 2$ |*12
4(x(x + 1)) + 3(8 + x) = 24
$4(x^2 + x) + 24 + 3x - 24 = 0$
$4x^2 + 4x + 24 + 3x - 24 = 0$
$4x^2 + 7x = 0$
$x(4x + 7) = 0$
x = 0 или 4x + 7 = 0
4x = −7
$x = -\frac{7}{4} = -1\frac{3}{4}$
Ответ:
$x_1 = 0$;
$x_2 = -1\frac{3}{4}$.