If f(x) is defined as follows, find (a) f(-4). (b) f(O), and (c) f(1).
x²
if x<0
f(x) = { -3
if x=0
2x+3 if x > 0
(a) f(-4)=(Simplify your answer.)
(b) f(0) = (Simplify your answer.)
(C) f(1) = (Simplify your answer.)