Réponse :
Bonjour,
a) 3x + 2 < x – 14
⇔ 3x – x < –14 – 2
⇔ 2x < – 16
⇔ x < –8
S = ] -∞ ; –8 [
b) –2x – 5 > 4x + 31
⇔ –2x – 4x > 31 + 5
⇔ –6x > 36
⇔ x < –6
S = ] -∞ ; –6 [
c) 9x + 19 < –x + 51
⇔ 9x + x < 51 – 19
⇔ 10x < 32
⇔ x < 32/10
⇔ x < 16/5
S = ] -∞ ; 16/5 [
d) –3x + 5 < –x + 17
⇔ –3x + x < 17 – 5
⇔ –2x < 12
⇔ x > –6
S = ] –6 ; +∞ [