Bonjour,
a) (2x-3)(3x+7)-2x+3 = (2x-3)(3x+7)-(2x-3)
= (2x-3)(3x+7)-(2x-3)1
= (2x-3)[(3x+7)-1]
= (2x-3)(3x+6)
= 3(2x-3)(x+2)
b) (5x-4)²-5x+4 = (5x-4)²-(5x-4)
= (5x-4)(5x-4)-(5x-4)1
= (5x-4)[(5x-4)-1]
= (5x-4)(5x-5)
c) (2x+7)²-2x-7+(3x-1)(2x+7) = (2x+7)²-(2x+7)+(3x-1)(2x+7)
= (2x+7)(2x+7)-(2x+7)1+(3x-1)(2x+7)
= (2x+7)[(2x+7)-1+(3x-1)]
= (2x+7)(5x+5)
tu essayes le dernier ?
