Verified answer

Bonjour !

5 - 7,5x = 2,5x + 15

5 - 7,5x - 2,5x = 2,5x + 15 - 2,5x

5 - 10x = 15

5 - 10x - 5 = 15 - 5

-10x = 10

-10x/10 = 10/10

-x = 1

x = -1

J'espère t'avoir aidé. Bon courage !