j'ai besoin daide svp​

Bonjour,
*= multiplication

1. (2x + 5)*2 + 2x
2*2x + 2*5 + 2x
4x + 10 +2x
6x + 10

2. 31= (2x + 5)*2 + 2x
31= 6x + 10
31 -10 = 6x
21/6 = 6x/6
3,5 = x