Answer:
2x
Step-by-step explanation:
f(x) = x -4
Step 1:
y = x - 4
Step 2: Replace y with x
x = y - 4
Step 3: Find y
x + 4 = y
f(-x) = x + 4
f(x) + f(-x) = (x - 4)+ (x + 4) = 2x
