Question

Evaluate f(x) = 2 x 4^x for x = -2

a. 0.225
b. 16
c. 0.125
d. -8

Answer 1

So plugging in the -2 for gives you 2 x 4^(-2)
This becomes 2 x 1/4^2
Why is it 1/4^2? Because a negative power means 1 over the value to that power. In this case the value is 4 and the power is 2.
Simplify further to get 2 x 1/16= 2/16=1/8=.0125