How to determine the linear functions of f(x) and h(x)?

Question

Determine if the linear functions f (x) and h (x) with the following values f (-2) = -4, f (0) = h (0) = 2 and h (2) = 8 define the same functions.

Answer 1

The first one is definitely not linear: f(0+-2) = f(-2) = -4, whereas f(0) + f(-2) = 2 + -4 = -2.

The second one is also not linear: h(0+2) = h(2) = 8, whereas h(0) + h(2) = 2 + 8 = 10.

So neither function is linear.