Question

Help math beats me up in dark alleys

Answer 1

Replace x with 3:

f(x) = 20(0.5)^x

f(3) = 20(0.5)^3

First do 0.5^3 = 0.125

Now multiply that by 20:

20 x 0.125 = 2.5

f(3) = 2.5