Hasyata

Bonjour !

a) 7x-6 = 4-3x

<=> 7x+3x = 4+6

<=> 10x = 10

<=> x = 10/10 = 1

b) 12-a = 18-3a

<=> 3a - a = 18-12

<=> 2a = 6

<=> a = 6/2 = 3

Voilà.