Đáp án:
Giải thích các bước giải:
$\text{2) 2x² + 3x - 27}$
$\text{= 2x² - 6x + 9x - 27}$
$\text{= 2x( x - 3) + 9(x - 3)}$
$\text{= (2x + 9) (x - 3)}$
$\text{3) x² - 10x + 24}$
$\text{= x² - 4x - 6x + 24}$
$\text{= x(x - 4) - 6( x - 4)}$
$\text{= (x - 6)(x - 4)}$
$\text{5) 2x² - 5xy - 3y²}$
$\text{= 2x² + xy - 6xy - 3y²}$
$\text{= x(2x + y) - 3y( 2x - y)}$
$\text{= ( x - 3y)(2x - y)}$
$\text{6) 3x² - 11x + 6}$
$\text{= 3x² - 9x - 2x + 6}$
$\text{= 3x(x - 3) - 2(x - 3)}$
$\text{= (3x - 2)(x-3)}$
$\text{8) x² + 5x + 6}$
$\text{= x² + 2x + 3x + 6}$
$\text{= x(x + 2) + 3(x + 2)}$
$\text{= (x + 3)(x + 2)}$
$\text{9) x² + 2x - 15}$
$\text{= x² + 5x - 3x - 15}$
$\text{= x(x + 5) - 3(x + 5)}$
$\text{= (x - 3)(x + 5)}$
$\text{11) x² - x - 6}$
$\text{= x² - 3x + 2x - 6}$
$\text{= x(x - 3)+2(x - 3)}$
$\text{= (x + 2)(x - 3)}$
$\text{12) x² - 9x + 14}$
$\text{= x² - 2x - 7x + 14}$
$\text{= x(x - 2) - 7(x - 2)}$
$\text{= (x - 7)(x - 2)}$
