10b solve the equation

AL2006

                                            39  =  (1 and 3/10) b

Let's change that ugly mixed number to a fraction
so that we can work with it.

                   (1 and 3/10)  =  (10/10 and 3/10)  =  13/10

Now the equation says     39  = 13/10  b  

We could multiple
each side by 10:              390  =  13 b

Divide each side by 13:    390 / 13  =  30  =  b

Whenever you're trying to solve any equation, the whole idea is: 

-- Do whatever you need to do in order to get the variable all alone
on one side of the equation and everything else on the other side. 

-- You can do anything you want to do on either side of the equation,

BUT ...

-- whatever you do to one side, you must IMMEDIATELY do the same thing
to the other side.