Step-by-step explanation
A piecewise defined function is a function divided into branches by certain conditional rules. The conditions stand after the conditional "if". To evaluate a piecewise defined function for a particular value, we need to know first which condition it satisfies, and then, apply its corresponding rule.
Here, we have the function

Let's begin the evaluations with -4. Note that it's less than 0, that is, it satisfies the first condition (x<0). By what I said before,

The next is f(-3). Again, -3<0. Thus

Now, 0 satisfies the second condition,

This means that we must apply the second rule (adding 2):

The next two numbers 3 and 4 satisfy the second condition as well (for they are positive). Then,

Answer
