First, Outer, Inner, Last
You are aware of PEMDAS (order of operations) where you work what is inside the parenthesis first, but what if you encounter a problem like this:
5x ( x + y – 4)
Instead of just working inside the parenthesis, you multiply the outside term by every term inside of the parenthesis. This involves multiplying just the numbers and adding the letters together. If the letters are alike, then create an exponent for the sum of those letters. This is just like the example on the previous page. Let’s repeat that: Multiply the numbers and add the letters when multiplying expressions.
5x² + 5xy -20x
Wait, Where Was the FOIL?
Utilize the FOIL method when you are multiplying expressions that each contain two terms together. Essentially, each term is getting multiplied by every possible combination.
(2x + 6)(3x + 8)
- FIRST 2x * 3x = 6x²
- OUTER 2x * 8 = 16x
- INNER 6 * 3x = 18x
- LAST 6 * 8 = 48
Add these terms together to get: 6x² + 34x + 48 for your answer.
Let’s have Liesel illustrate one more example:
