Respuesta :
Since you don't know the value of b about the best that you could do is:
(2b)^4
16b^4
16b*b*b*b
(2b)^4
16b^4
16b*b*b*b
you will write 2b. 2b. 2b. 2b because all you are doing is multiplying 2b by itself 4 times. 2b.2b.2b.2b