re

f (2) = - 2

f ( - 2 ) = 2

antécédents de - 2 = -4 ; 0 ; 2

f (x) = 1

f(-3); f( -1) ; f (3) = 1

g (x) = 2

g ( -1.5) ; g (3.5) = 2

g (x) = - 3

g ( - 4.2 env) ; g ( 1) = - 3

f (x) = g (x)

en - 1 ; 0