Sagot :

n°28 :
a) f(-1) = 1
b) f(0) = 3
c) f(-1,5) = 1 et f(1,5) = 1
d) f(0) = 3

n°29 :
a) g(0) = 3
b) g(1) = 1,5 et g(-2) = 1
c) g(3) = -1 ; g(-2) = 1 ou g(1,5) = 1 ; g(0) = 5