bonjour
( 3 x + 1 ) ² = 9 x² + 6 x + 1
si x = 0
( 1)² = 1 ²
1 = 1 donc vrai
si x = 1
4 ² = 9 + 6 + 1
16 = 16
donc solution
si x = 2
7 ² = 36 + 12 + 1
49 = 49
