Substracting, adding and multiplication with letters

When calculating with letters it’s important to know what “like terms” are.

Like terms are terms that have the same letters (and those letters have the same powers)

E.g. 3a and 8a and 333a are like terms. But 12a and 4ab and 9c and 12a2 are not like terms.

 

The rules of calculating with letters tell us we can only add like terms and we can multiply all terms. But as with all calculations we make, we should always remember the order of operations!

So, when we have an equation where we both multiply and add terms we should first think about the order of operations and so in which order should we do our calculations. Then when we established the order we should check if we are dealing with addition, in which case we can only add like terms, or multiplication, in which case we can just do that multiplication.

 

E.g. 

 

Solution:
So first we look at the order of operation. This means we first have to multiply. So

And we can’t simplify it any further.