Question

What is the value of f(-2) for the given function

Answer 1

Copy down the given function:

f(x)=3•2^x

Now replace both instances of x with -2:

f(-2) = 3*2^(-2).                                1

Recall that 2^(-2) is the same as ------ = 1/4

                                                      2^2

Therefore, f(-2) = 3*2^(-2) = 3*(1/4) = 3/4

Remember that exponentiation has to be carried out before multiplication.  That's why I did 2^(-2) before multiplying by 3.