e) x² + x - 6 = x² - 2x + 3x - 6 = x( x - 2 ) + 3( x - 2 ) = ( x - 2 )( x + 3 )
g) 2x² + 7x + 6 = 2x² + 4x + 3x + 6 = 2x( x + 2 ) + 3( x + 2 ) = ( x + 2 )( 2x + 3 )
h) -2x² - 3x + 5 = -2x² + 2x - 5x + 5 = -2x( x - 1 ) - 5( x - 1 ) = ( x - 1 )( -2x - 5 )
i) x² - 6x + 5 = x² - x - 5x + 5 = x( x - 1 ) - 5( x - 1 ) = ( x - 1 )( x - 5 )
k) 4x² - 4x - 3 = ( 4x² - 4x + 1 ) - 4 = ( 2x - 1 )² - 2² = ( 2x - 1 - 2 )( 2x - 1 + 2 ) = ( 2x - 3 )( 2x + 1 )
l) 3x² - 8x + 4 = 3x² - 6x - 2x + 4 = 3x( x - 2 ) - 2( x - 2 ) = ( x - 2 )( 3x - 2 )
m) 2x² + 3x - 5 = 2x² - 2x + 5x - 5 = 2x( x - 1 ) + 5( x - 1 ) = ( x - 1 )( 2x + 5 )
n) 25^x - 6.5^x + 5 ( tịt r :)) )