bonjour
f 1 ( x) = [ 2 ( 6 - x ) ] / 2 = ( 12 - 2 x ) / 2 = - x + 6
f 2 ( x) = 8 x /2 = 4 x
aire trapèze = [ ( 8 + 2 ) x 6 ] / 2 = 60 /2 = 30
f 3 (x) = 30 - ( - x + 6 + 4 x ) = 30 + x - 6 - 4 x = - 3 x + 24
aire T1 ≤ T 2
- x + 6 ≤ 4 x
- x - 4 x ≤ - 6
- 5 x ≤ - 6
x ≥ 6 /5
T2 ≤ T 3
4 x ≤ - 3 x + 24
4 x + 3 x ≤ 24
7 x ≤ 24
x ≤24/7
bonne journée
