Answer:
steps below
Step-by-step explanation:
This is a contradictory proof of sophistry
f(x+4) = f(x)+f(4) ...(1) when x=0
f(x+4) = f(0+4) = f(4) = f(x) + f(4)
f(x) = f(4)-f(4) = 0
From (1): f(x) = f(x+4) - f(4)
x=-4 f(-4) = f(-4+4) - f(4) = f(0) - f(4) = -f(4) ...(2)
From (1): f(x+4) = f(x)+f(4)
x=4 f(4+4) = f(8) = f(4) + f(4) = 2f(4) = -2f(-4) from (2) ... (3)
f(8) +2f(-4) = -2f(-4) + 2f(-4) = 0
