Réponse :
Explications étape par étape
Bonjour,
5y - 9 = 2y
5y - 2y - 9 = 2y - 2y
3y - 9 + 9 = 0 + 9
3y = 9
3y/3 = 9/3
y = 3
y² = 2y
y² - 2y = 0
y(y - 2) = 0
y = 0 ou y - 2 = 0
y = 0 ou y = 2
4y - 7 = y/2 + 7
4y - y/2 = 7 + 7
8y/2 - y/2 = 14
7y/2 = 14
y = 14 * 2/7
y = 4
6(y + 1) = 8y + 4
6y + 6 = 8y + 4
6 - 4 = 8y - 6y
2 = 2y
y = 2/2
y = 1