sorry, should actually read:

2exponent b =

48 exponent 5
______________

12 expnent 5

I am not sure that you have posted the correct question...
"2 exponent b + 48 exponent 5 = 12 expnent 5"

I think the question should read:

If 2^b = (48^5)/(12^5), what's the value of b?

Let's start by simplifying the right side of the equation:

48^5 = (12^5)(4^5)

So, 48^5/12^5 = (12^5)(4^5)/12^5 = 4^5

To make the right side comparable to the left, let's do:

4^5 = (2^2)^5 = 2^(2*5) = 2^10

Now we have:

2^b = 2^10

and b=10.

Yes I agree with stuart...

Suggest me if iam wrong.

thanks so much...I get it now..much appreciated.