express (-5/2)^4 - 2^(-4) in the form a/b, where...

Alright so as a practice problem we were given this question:

Express the number in the form a/b, where a and b are integers.

(-5/2)^4 -2^-4

The answer I got at first was 39, but according to the online answer was wrong. Does anyone know how this problem can be done with the conditions given

Re: problem help

Hello, gierhame!

Your answer is correct,
. . but did you have a denominator in your answer?

\(\displaystyle \text{Express the number in the form }\frac{a}{b}\text{, where }a \text{ and }b\text{ are integers: }\;\left(\text{-}\frac{5}{2}\right)^4 - 2^{-4}\)

Click to expand...

\(\displaystyle \text{We have: }\;\frac{(\text{-}5)^4}{2^4} - \frac{1}{2^4} \;\;=\;\;\frac{625}{16} - \frac{1}{16} \;\;=\;\;\frac{624}{16} \;\;=\;\;\frac{39}{1}\)