(2x-5y)^2 Answer

3 min read Jun 16, 2024
(2x-5y)^2 Answer

Expanding the Square of a Binomial: (2x - 5y)^2

The expression (2x - 5y)^2 represents the square of a binomial, which is a polynomial with two terms. To expand this expression, we can utilize the concept of FOIL (First, Outer, Inner, Last) or the square of a difference formula.

Expanding using FOIL

FOIL stands for:

  • First: Multiply the first terms of each binomial.
  • Outer: Multiply the outer terms of the binomials.
  • Inner: Multiply the inner terms of the binomials.
  • Last: Multiply the last terms of each binomial.

Applying FOIL to (2x - 5y)^2:

  1. First: (2x) * (2x) = 4x^2
  2. Outer: (2x) * (-5y) = -10xy
  3. Inner: (-5y) * (2x) = -10xy
  4. Last: (-5y) * (-5y) = 25y^2

Adding the results:

4x^2 - 10xy - 10xy + 25y^2 = 4x^2 - 20xy + 25y^2

Using the Square of a Difference Formula

The square of a difference formula states: (a - b)^2 = a^2 - 2ab + b^2

In this case, a = 2x and b = 5y. Applying the formula:

(2x - 5y)^2 = (2x)^2 - 2(2x)(5y) + (5y)^2

Simplifying:

(2x - 5y)^2 = 4x^2 - 20xy + 25y^2

Conclusion

Both methods yield the same answer: 4x^2 - 20xy + 25y^2. Expanding (2x - 5y)^2 results in a trinomial, where the first and last terms are squares of the original binomial terms, and the middle term is twice the product of the original terms. Remember, when squaring a binomial, it's crucial to remember the sign of the middle term, which is negative in this case.

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