Réponse :
bonjour
a) 2 x + 5 = - 7
2 x = - 7 - 5
2 x = - 12
x = - 6
b) 5 x +4 = 16 - 3 x
5 x + 3 x = 16 - 4
8 x = 12
x = 12/8 = 3 /2
c) x ( x + 2 ) = x² + 63
x² + 2 x = x² + 63
x² - x² + 2 x = 63
2 x = 63
x = 63/2
d) 3 (5 - 2 x ) = 4 x + 6
15 - 6 x = 4 x + 6
- 6 x - 4 x = 6 - 15
- 10 x = - 9
x = 9/10
e) x² = 49
x = √49 ou - √49
x = 7 ou - 7
f) 3 x² - 75 = 0
3 x² = 75
x² = 25
x = √25 ou - √25
x = 5 ou - 5
Explications étape par étape :
