Réponse :
Bonjour,
Exercice 1 :
3x + 10 = 5x-70
3x-5x = -70-10
-2x = -80
2x = 80
x = 40
18x + 4 = 34x - 4
18x - 34x = -8
-16x = -8
x = 8/16 = 0.5
x/2 + 3x/4 - 5x/7 = 20
2X+3X/4 -5X / 7 = 20
35x - 20x /28 = 20
15x/ 28 = 20
15x = 20 * 28
x = -560/15 = -112 / 3
(x-1)(x-2) = x² - 4
x² - 2x - x + 2 = x² - 4
-3x = -6
x = 2
Exercice 2
x doit être different de 0 dans le premier cas.
3x-16 = 5/3 * x
3X- 16 = 5x / 3
15x - 48 = 5x
10x = 48
x = 48/10 = 4.8
x doit être différent de - 1 dans le second cas
5x - 5 = 3(x+1)
5x - 3x = 3 + 5
2x = 8
x = 4.
Bon courage
