Réponses

2014-01-03T17:39:17+01:00
A = ( 2x - 7 )( 3x + 6 ) - 2( 2x + 4 )( 2x - 8 )
= 3( 2x - 7 )( x + 2 ) - 4( x + 2 )(2x - 8)
= ( x + 2 )( 6x - 21 - 8x + 32 )
A = ( x + 2 )( 11 - 2x )

B = 9x² + 6x + 1 - ( 5x+7 )( 6x + 2)
= ( 3x + 1 )² - 2( 5x + 7)( 3x + 1)
= ( 3x + 1)(3x + 1 - 10x - 14 )
B = -( 3x + 1)(13 + 7x )

C = x(6x + 5) + 4x(x - 4)
= x ( 6x + 5 + 4x - 16x )
C = x ( 5 -6x )