Well what i think you're asking here...I apologie if I'm wrong but what I did was
f(-1) = 4 * 7^t = 4/7
and
f(2) = 4 * 7^t = 196.
Is this what you wanted if not I can...try another way.
Answer:
Expressing a number in a power of 2 means that you have to figure out how many times you should multiply 2 by itself so the product will be that number.
The number is expressed as 2^n
For example:
Express 16 as a power of 2:
To get 16, you have to multiply 2 by 4 times.
2 × 2 × 2 × 2 = 16
16 = 2^4
Then the answer is 2^4