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M = ( 3x + 5 )² - ( 3x + 5 ) ( 2x + 7 )

1)
M = ( 3x + 5 )² - ( 3x + 5 ) ( 2x + 7 )
M = ( 3x + 5 )  [ 1 - ( 2x + 7) ]
M = ( 3x + 5 ) ( - 2x - 8 )
M = -6x² - 24x - 10x - 40
M = -6x² - 34x - 40

2)
M = 2 ( -3x² - 17x - 20 )

3)
Pour x = 2
M = 2 ( -3 * 2² - 17 *2 - 20 )
M = 2 ( -12 - 34 - 20 )
M = 2 * -66
M = - 132