To get, say, x on its own you need to collect all the x terms together (but in this case there's only one anyway) and then 'undo' it. So to get x from 3x divide by 3. Since 3x = wyz you divide wyz by 3 as well. So x = wyz/3.

To get w on its own, write wyz as w(yz) and divide through by (yz). So 3x = w(yz) implies 3x/(yz) = w.