Réponse :
Explications étape par étape
Bonsoir
Résoudre :
(15 - 5x)(x + 1) > 0
15 - 5x = 0
15 = 5x
x = 15/5
x = 3
x + 1 = 0
x = -1
x..........|-inf............(-1)............3............+inf
15-5x..|........(+)..............(+).....o....(-).........
x+1......|........(-)........o.....(+)...........(+)........
Ineq..|..........(-).......||......(+).....||.....(-).......
[tex]x \in ]-1 ; 3[[/tex]
(2x + 4)(3x - 3) [tex]\ge[/tex] 0
2x + 4 = 0
2x = -4
x = -4/2
x = -2
3x - 3 = 0
3x = 3
x = 3/3
x = 1
x...........|-inf...........(-2)...............1............+inf
2x+4....|........(-).......o......(+)..........(+)........
3x-3.....|........(-)................(-)......o...(+)........
Ineq....|.........(+)......o.......(-)......o...(+).......
[tex]x \in ]-\infty ; -2] U [1 ; +\infty[[/tex]
