$2x^2 - 5x + 2 = 0$
$2x^2 - 4x - x + 2 = 0$
$(2x^2 - 4x) - (x - 2) = 0$
2x(x − 2) − (x − 2) = 0
(x − 2)(2x − 1) = 0
x − 2 = 0
x = 2
или
2x − 1 = 0
2x = 1
$x = \frac{1}{2}$
Ответ: $\frac{1}{2}; 2$.

$3x^2 + 10x + 3 = 0$
$3x^2 + 9x + x + 3 = 0$
$(3x^2 + 9x) + (x + 3) = 0$
3x(x + 3) + (x + 3) = 0
(x + 3)(3x + 1) = 0
x + 3 = 0
x = −3
или
3x + 1 = 0
3x = −1
$x = -\frac{1}{3}$
Ответ: $-3; -\frac{1}{3}$.

$4x^2 + 5x - 6 = 0$
$4x^2 + 8x - 3x - 6 = 0$
$(4x^2 + 8x) - (3x + 6) = 0$
4x(x + 2) − 3(x + 2) = 0
(x + 2)(4x − 3) = 0
x + 2 = 0
x = −2
или
4x − 3 = 0
4x = 3
$x = \frac{3}{4}$
Ответ: $-2; \frac{3}{4}$.

$3x^2 - x - 2 = 0$
$3x^2 - 3x + 2x - 2 = 0$
$(3x^2 - 3x) + (2x - 2) = 0$
3x(x − 1) + 2(x − 1) = 0
(x − 1)(3x + 2) = 0
x − 1 = 0
x = 1
или
3x + 2 = 0
3x = −2
$x = -\frac{2}{3}$
Ответ: $-\frac{2}{3}; 1$.