Sagot :
Réponse :
Bonsoir
1) A(x) = 0
⇔ (2x + 3)/(x + 7) = 0
⇔ 2x + 3 = 0
⇔ x = -3/2
2) A(x) = 3
⇔ (2x + 3)/(x + 7) = 3
⇔ (2x + 3)/(x + 7) - 3 = 0
⇔ (2x + 3)/(x + 7) - 3(x + 7)/(x + 7) = 0
⇔ (2x + 3 - 3x - 21)/(x + 7) = 0
⇔ -x - 18 = 0
⇔ x = -18
3) A(x) = -2
⇔ (2x + 3)/(x + 7) = -2
⇔ (2x + 3)/(x + 7) + 2 = 0
⇔ (2x + 3)/(x + 7) + 2(x + 7)/(x + 7) = 0
⇔ (2x + 3 + 2x + 14)/(x + 7) = 0
⇔ 4x + 17 = 0
⇔ x = -17/4