Sagot :
(x-3)/(x+5) - (x-4)/x+2) < 0
[(x-3)(x+2) - (x-4)(x+5)]/(x+2)(x+5)< 0
(x² - x - 6 - x² - x + 20 ) /(x+2)(x+5)< 0
(-2x+14)/(x+2)(x+5)< 0
ici il faut un tableau de signes
x -5 -2 7
-2x+14 + + + 0 -
x+2 - - 0 + +
x+5 - 0 + + +
Expression + | - | + 0 -
solution ]-5; -2[ U [7; infini
(x - 3) / (x + 5) <= (x - 4) / (x + 2) je fais le produit en croix
(x - 3) x ( x + 2) <= (x - 4) x (x + 5)
x² + 2x - 3x - 6 <= x² + 5x - 4x - 20
x² - x² + 2x - 3x - 5x + 4x <= -20 + 6
-2x <= -14
x <= -14 / (-2)
x <= 7