nathalienouts
Ex 1 1)4x²-9-(2x+3)(x-1) ⇔ 4x²-9-(2x²-2x+3x-3) ⇔4x²-9-2x²-x+3 ⇔2x²-x-6
2) a) 4x²-9 = (2x)²-3² identité remarquable a²-b²= (a+b)(a-b) = (2x+3)(2x-3) b) 4x²-9-(2x+3)(x-1) ⇔(2x+3)(2x-3)-(2x+3)(x-1) on met 2x+3 en facteur ⇔(2x+3)(2x-3-x+1) ⇔ (2x+3)(x-2)
Lista de comentários
1)4x²-9-(2x+3)(x-1)
⇔ 4x²-9-(2x²-2x+3x-3)
⇔4x²-9-2x²-x+3
⇔2x²-x-6
2)
a) 4x²-9 = (2x)²-3² identité remarquable a²-b²= (a+b)(a-b)
= (2x+3)(2x-3)
b)
4x²-9-(2x+3)(x-1)
⇔(2x+3)(2x-3)-(2x+3)(x-1) on met 2x+3 en facteur
⇔(2x+3)(2x-3-x+1)
⇔ (2x+3)(x-2)