Resposta :
a) f(0) = 3*0 + 15
f(0) = 15
b) f(0) = -4*0 + 12
f(0) = 12
c) f(0) = 5*0 - 7
f(0) = -7
d) f(0) = -5*0
f(0) = 0
f(0) = 15
b) f(0) = -4*0 + 12
f(0) = 12
c) f(0) = 5*0 - 7
f(0) = -7
d) f(0) = -5*0
f(0) = 0