i'll do the first.

f(-3) means we want the value of the function when x = -3. since this is a piece-wise defined function, i have to look for what formula gives the value of the function at x = -3. clearly, x < 0 is the only interval that covers x = -3, so i look at the formula for that interval, which is x + 2.

thus, f(-3) = (-3) + 2 = -1

now do the rest