a)

b)

c)

fa1(x) = 2^(x)
fa2(x) = 2^(x) - 1
fa3(x) = 2^(x) + 1
a = false
fb2(x) = 2^(x - 1)
fb3(x) = 2^(x + 1)
fb1(x) = 2^(x)
b = false
fc1(x) = 2^(x)
fc2(x) = (-2^(x))
fc3(x) = 2^((-x))
c = false