Substitute the given value of x in the question to the piecewise function. i.e Substitute (-4) to all the values of x in the function. Then, see which inequality satisfies f(-4). The only inequality that satisfies f(-4) is x<-3, Since -4<-3, which is true. Therefore the answer to this question would be the corresponding relation, i.e x + 2 -----> (-4) + 2 = -2.
f(-4) = -2
Do the same for the other questions and you will get:
f(4) = -4 and f(0) = -4