1°
(2x-1)(x+3)>(2x-1)(5-4x)
(2x-1)(x+3)-(2x-1)(5-4x)>0
(2x-1)[(x+3)-(5-4x)>0
(2x-1)(x+3-5+4x)>0
(2x-1)(5x-2)>0
Tableau de signe :
S=]-infini;2/5[U]1/2;+infini[
2°
(x+1)²>=(3-5x)²
(x+1)²-(3-5x)²>=0
[(x+1)-(3-5x)]*[(x+1)+(3-5x)]>=0
(x+1-3+5x)(x+1+3-5x)>=0
(6x-2)(-4x+4)
Tableau de signe :
S=[1/3;1]