bonjour,
1) 4-x² =a²-b²
(2-x)(2+x)
2) 16a²-49 =
4a-7)(4a+7)
3) 16a²-49b² =
(4a-7b)(4a+7b)
4) x²-3 =
(x-√3)(x+√3)
5) (2x+1)²-49 =
(2x+1-7)(2x+1+7) =
(2x-6)(2x+8)
6) idem 5 , à faire
7) (4x-5-2x-3)(4x-5+2x+3) =
(2x-8)(6x-2)
8)(2x-√3-√3)(2x-√3+√3)=
(2x-2√3)(2x)
9) (4x+1-x+3)(4x+1+x-3) =
(3x+4)(5x-2)
