40đ giúp mk nha mk năn nỉ các bạn đấy!

$\text{→ Đáp án + Giải thích các bước giải:}$

$\text{a)}$

$\text{( 6x + 1 )² + ( 6x - 1 )² - 2( 1 + 6x )( 6x - 1 )}$

$\text{= ( 1 + 6x )² - 2( 1 + 6x )( 6x - 1 ) + ( 6x - 1 )²}$

$\text{= ( 1 + 6x - 6x + 1 )² = 2² = 4.}$

$\text{b) 3x( x - 2 ) - 5x( 1 - x ) - 8( x² - 3 )}$

$\text{= 3x² - 6x - 5x + 5x² - 8x² + 24}$

$\text{= - 11x + 24}$

$\text{c)}$

$\text{( 7x - 3 )( 2x + 1 ) - ( 5x - 2 )( x + 4 ) - 9x² + 17x}$

$\text{= 14x² + 7x - 6x - 3 - ( 5x² + 20x - 2x - 8 ) - 9x² + 17x}$

$\text{= 5x² + 18x - 3 - 5x² - 18x + 8}$

$\text{= 5}$

$\text{d)}$

$\text{( 6x - 5 )( x + 8 ) - ( 3x - 1 )( 2x + 3 ) - 9( 4x - 3 )}$

$\text{= 6x² + 48x - 5x - 40 - ( 6x² + 9x - 2x - 3 ) - ( 36x - 27 )}$

$\text{= 6x² + 43x - 40 - 36x + 27 - 6x² - 7x + 3}$

$\text{= -10}$

$\text{e) -3( x + 2 )² + ( x + 3 )( x - 1 )( x + 1 ) - ( 2x - 3 )²}$

$\text{= -3( x² + 4x + 4 ) + ( x + 3 )( x² - 1 ) - ( 4x² - 12x + 9 )}$

$\text{= -3x² - 12x - 12 + x³ - x + 3x² - 3 - 4x² + 12x - 9}$

$\text{= x³ - 4x² - x - 24.}$