Question
Qn. f(x + y) = f(x)f(y)
for all x, y, f(4) = +3 what is f(-8)?
A. 1/3
B. 1/9
C. 9
D. 6
Answer Choice: B
Explanatory Answer
f(x + 0) = f(x) f(0)
f(0) = 1
f(4 + -4) = f(0)
f(4 + -4) = f(4) f(-4)
1 = +3 x f(-4)
f(-4) = 1/3
f(-8) = f(-4 + (-4)) = f(-4) f(-4)
f(-8) = 1/3 x 1/3 = 1/9
Answer Choice (B)