Réponse :
bonsoir
f (x) = 3 x - 5
f ( - 7 ) = - 21 - 5 = - 26
f (2.1 ) = 6.3 - 5 = 1.3
f ( 2/5 ) = 6/5 - 5 = 6/5 - 25/5 = - 19/5
3 x - 5 = 16
3 x = 16 + 5
3 x = 21
x = 7
3 x - 5 = 5
3 x = 5 + 5
3 x = 10
x = 10/3
f (x) = 2 x /5 - 1 /3
f ( 5 ) = 10 /5 - 1 /3 = 2 - 1/3 = 6/3 - 1 /3 = 5/3
f ( - 15 ) = - 30 /5 - 1/3 = - 6 - 1/3 = - 18/3 - 1/3 = - 19/3
f ( 5/4 ) = 10/20 - 1/3 = 30/60 - 20/60 = 10/60 = 1/6
2 x /5 - 13/3 = 2 /3
6 x /15 - 65/15 = 10/15
6 x = 10 + 65
6 x = 75
x = 75/6 = 12.5
2 x /5 - 1 /3 = 0
6 x /15 - 5/15 = 0
6 x = 5
x = 5/6
Explications étape par étape :
