My book says the second step precedes like this
Maybe I'm not at the level you think I am, because my problem is really how to multiplicate those parentheses.. the bold written line.. I don't know the way it's done.
Ok, first write that properly:
What has been done between lines 1 & 2:
To get 2, you simply multiply both sides by . This is one way of solving an equation with fractions.
From there, you need to simplify the expression. Cross out terms... and get rid of the fractions:
That done, multiply the terms and finish to solve!