You may have previously seen that , but what is ? If you write as , you can use what you learned about the distributive property of multiplying parentheses to find the answer:
This also applies to :
These results are used all the time in mathematics, and we call them the first and second algebraic identities. Learn these, and you’ll save a lot of time you would’ve spent calculating!
If you apply the first and second algebraic identities to the squared parentheses, you get