Đáp án +Giải thích các bước giải:
$\text{1 ) x² - 2x + x - 2}$
$\text{= ( x² + x ) - ( 2x + 2 )}$
$\text{= x.( x + 1 ) - 2.( x + 1 )}$
$\text{= ( x + 1 ) . ( x - 2 )}$
$\text{2 ) 2x² - 2x + 5 - 5x}$
$\text{= ( 2x² - 2x ) + ( 5 - 5x )}$
$\text{= 2x ( x - 1 ) + 5. ( 1 - x )}$
$\text{= 2x ( x - 1 ) - 5. ( x - 1 )}$
$\text{= ( x - 1 ) . ( 2x - 5 )}$
$\text{3 ) x² + 6x + 9 - 16 }$
$\text{= ( x² + 6x + 9 ) - 4²}$
$\text{= ( x + 3 )² - 4²}$
$\text{= ( x + 3 -4 ) . ( x + 3 + 4 )}$
$\text{= ( x - 1 ) . ( x + 7 )}$
$\text{4 ) $x^{4}$ + x³ + x + 1 }$
$\text{= ( $x^{4}$ + x³ ) + ( x +1 )}$
$\text{= x³ ( x + 1 ) + ( x +1 ) }$
$\text{= ( x +1 ) . ( x³ + 1 )}$
$\text{= ( x +1 ) . ( x + 1 ) . ( x² - x +1 ) }$
$\text{= ( x + 1 )² ( x² - x + 1 )}$
$\text{5 ) 2x² + 3x - 2x - 3 }$
$\text{= ( 2x² - 2x ) + ( 3x - 3 )}$
$\text{= 2x ( x - 1 ) + 3 ( x - 1 )}$
$\text{= ( x - 1 ) . ( 2x + 3 )}$
$\text{6 ) x² - y² - 2x - 2y }$
$\text{= ( x² - y² ) - ( 2x + 2y)}$
$\text{= ( x² - y² ) - 2( x + y )}$
$\text{= ( x + y ) . ( x - y ) - 2 ( x + y )}$
$\text{= ( x + y ) . ( x - y - 2 )}$
$\text{7 ) x³ - 4x² + 8x + 8 }$
$\text{= x³ + 2³ - 4x² + 8x}$
$\text{= ( x + 2 ). ( x² - 2x + 4 ) - 4x ( x + 2 )}$
$\text{= ( x + 2 ) . ( x² - 2x + 4 - 4x ) }$
$\text{= ( x + 2 ) . ( x² - 6x + 4 ) }$
Bạn xem lại đề bài 7 nha
