Greetings math friends! This post will go over how to expand and simplify cubed binomials 2 different ways. We’re so used to seeing squared binomials such as, , and expanding them without a second thought. But what happens when our reliable squared binomials are now raised to the third power, such as,? Luckily for us, there is a Rule we can use:
But where did this rule come from? And how can we so blindly trust it? Which is why we are going to prove the above rule here and now using 2 different methods:
Why bother? Proving this rule will allow us to expand and simplify any cubic binomial given to us in the future! And since we are proving it 2 different ways, you can choose the method that best works for you.
Method #1: The Box Method
Method #2: The Distribution Method
Now that we’ve gone over 2 different methods of cubic binomial expansion, try the following practice questions on your own using your favorite method!
Practice Questions: Expand and simplify the following.
Still, got questions? No problem! Check out the video above or comment below! Happy calculating! 🙂
**Bonus: Test your skills with this Regents question on Binomial Cubic Expansion!