TI 89 for Statistics > How To Expand A Binomial On The TI-89

A binomial is a type of polynomial that has two terms (bi means two), usually joined by a plus or a minus sign. For example, 4x + 10 and 3x – 8 are both binomials. If a binomial has been raised to a large power, such as (3x – 8)^{10} and you want to expand it, you *could* work it out by hand using the binomial theorem. However, this could take you several minutes. Expand a binomial on the TI-89 in seconds.

## How To Expand A Binomial On The TI-89: Steps

Example question: Expand the following binomial function: f(x) = (2y + 3)(5y + 6)

Step 1: Press the HOME key.

Step 2: Press F2 and then press 3 to access the “expand” function.

Step 3: Press ( 2 y + 3 ) ( 5 y + 6 ) ) to enter the function.

Step 4: Press ENTER. Your answer will be 10y^2 + 27y + 18.

That’s it! You’re done!

***Note**: A “function” on the TI-89 isn’t quite the same thing as a mathematical function.

- A (mathematical) function is a type of equation or formula that has exactly one output (y) for every input (x).
- A TI-89 function (like the one used here) calculates a result, which in this case is a binomial probability. Software functions don’t have to obey the “one output” rule.

## References

Deviant, S. (2010). The Practically Cheating Statistics Handbook TI-89 Companion Guide.