bonjour,
f (3) = 0 et f ( 1) = - 1
( - 1 - 0) / ( 1 - 3 ) = - 1 / - 2 = 1/2
coefficient directeur a = 1/2
f ( 3) = 0
3 * 1/2 + b = 0
b = - 3/2
f( x) = x /2 - 3/2
f (x) = 1
x/2 - 3 /2 = 1
0.5 x = 1 + 3/2
0.5 x = 1 + 1.5
0.5 x = 2.5
x = 5
f (x) ≤ 2
x/2 - 3 /2 ≤ 2
0.5 x ≤ 2 + 1.5
0.5 x ≤ 3.5
x ≤ 7
] - ∞ : 7 ]
