Pour le a): (1/x)+ (4x-5)/4x <0 (4/4x)+ (4x-5)/4x <0 (4+4x-5)/4x <0 4+4x-5<0 4x < 5-4 4x <1 x<1/4
Pour le b): 3x²+ 1/(x+1) -3x <=0 (3x²(x+1)+1-3x(x+1))/(x+1) <=0 (3x^3+3x²+1-3x²-3x)/(x+1)<=0 (3x^3+1-3x)/(x+1)<=0 3x^3+1-3x<=0 3x(x²-1)<= -1 on a 3x<= -1 ou x²-1<=-1 x<= -1/3 ou x²<=0 x<=0
Lista de comentários
Pour le a):
(1/x)+ (4x-5)/4x <0
(4/4x)+ (4x-5)/4x <0
(4+4x-5)/4x <0
4+4x-5<0
4x < 5-4
4x <1
x<1/4
Pour le b):
3x²+ 1/(x+1) -3x <=0
(3x²(x+1)+1-3x(x+1))/(x+1) <=0
(3x^3+3x²+1-3x²-3x)/(x+1)<=0
(3x^3+1-3x)/(x+1)<=0
3x^3+1-3x<=0
3x(x²-1)<= -1
on a 3x<= -1 ou x²-1<=-1
x<= -1/3 ou x²<=0
x<=0