When you look at the question it probably looks strange, because when some number (
You might be asking how this is possible?
This is a clue that
Adding a negative number is the same as subtracting a positive, which you are more used to doing.
To solve the equation:
We want to get
In an equation, you can do ANY operation you like, as long as you do the same on both sides, to keep the equation in balance.
We need to get rid of the
This is the same as: