Expanding (x - 5y)^2
In mathematics, squaring a binomial like (x - 5y)^2 often requires understanding the concept of FOIL (First, Outer, Inner, Last). This method helps us systematically multiply the terms within the binomial.
Here's how to expand (x - 5y)^2 using FOIL:
- First: Multiply the first terms of each binomial: x * x = x²
- Outer: Multiply the outer terms of the binomials: x * (-5y) = -5xy
- Inner: Multiply the inner terms of the binomials: (-5y) * x = -5xy
- Last: Multiply the last terms of each binomial: (-5y) * (-5y) = 25y²
Now, we combine all the terms: x² - 5xy - 5xy + 25y²
Finally, simplify by combining the like terms: x² - 10xy + 25y²
Therefore, the expanded form of (x - 5y)² is x² - 10xy + 25y².
Key Points:
- Remember FOIL: This method helps ensure you multiply every term in the binomials.
- Simplify: Always combine like terms for a simplified answer.
- Practice: Expanding binomials becomes easier with practice.