Let
f(x) = 4x + 1 if x <=3
f(x) = 18 - 4x if x > 3
Find the sum of all values of x such that f(x) = 0.
Set the pieces = 0 to see if they qualify
4x+1 = 0
x = -1/4 this piece was for x <= 3 so x = -1/4 is one answer
18-4x = 0
x = 4 1/2 this piece was for x > 3 so x = 4 1/2 is another answer
-1/4 + 4 1/2 = __________