How do you work out -4(-5-b)=1/3(b+16)

First multiply the parenthesis:

20 - b = 1/3b + 16/3

Then combine like terms:

20 -b + b = 1/3b + b + 16/3

20 - 16/3 = 1/3b + b + 16/3 -16/3

20 - 16/3 = 1/3b + b

 44/3  =  4/3b

and if your looking for b;

44/3 (divided by) 4/3 = b

11 = b...is your final answer!

hope it helped :)