Expanding (x+2y)(x-2y)
The expression (x+2y)(x-2y) represents the product of two binomials. To expand this, we can use the FOIL method, which stands for First, Outer, Inner, Last.
Here's how it works:
- First: Multiply the first terms of each binomial: x * x = x²
- Outer: Multiply the outer terms of the binomials: x * -2y = -2xy
- Inner: Multiply the inner terms of the binomials: 2y * x = +2xy
- Last: Multiply the last terms of the binomials: 2y * -2y = -4y²
Now, combine all the terms:
x² - 2xy + 2xy - 4y²
Notice that the -2xy and +2xy terms cancel each other out. This leaves us with:
x² - 4y²
Therefore, the expanded form of (x+2y)(x-2y) is x² - 4y².
Important Note: The result we obtained is a classic example of the difference of squares pattern. This pattern states that: (a + b)(a - b) = a² - b²
In our case, 'a' is 'x' and 'b' is '2y'. Recognizing this pattern allows you to expand similar expressions quickly and efficiently.