Bonjour,
Factoriser :
= (6x+2)(3x-8)-(6x+2)(-7x-9)
= (6x+2)(3x-8-(-7x-9))
= 2(3x+1)(3x-8-(-7x-9))
= 2(3x+1)(3x-8+7x+9)
= 2(3x+1)(10x-8+9)
= 2(3x+1)(10x+1)
Bonne journée.