(x+1) (x-1) Foil Method

2 min read Jun 16, 2024

Understanding the FOIL Method with (x+1)(x-1)

The FOIL method is a mnemonic acronym that stands for First, Outer, Inner, Last. This method helps us multiply two binomials, which are expressions with two terms.

Let's explore the FOIL method with the example of (x+1)(x-1):

Steps of the FOIL Method

First: Multiply the first terms of each binomial.
- In our example: x * x = x²
Outer: Multiply the outer terms of the binomials.
- In our example: x * -1 = -x
Inner: Multiply the inner terms of the binomials.
- In our example: 1 * x = x
Last: Multiply the last terms of each binomial.
- In our example: 1 * -1 = -1

Combining the terms

After applying the FOIL method, we get the following expression:

x² - x + x - 1

Notice that the -x and +x terms cancel each other out.

Simplified Result

Therefore, the simplified result of (x+1)(x-1) using the FOIL method is:

x² - 1

Key takeaways

The FOIL method is a systematic way to multiply binomials.
It helps us remember to multiply all possible combinations of terms.
By simplifying the result, we can often obtain a simpler polynomial expression.

Remember to practice the FOIL method with various examples to solidify your understanding.