Math Problem Statement

Express the product (√5 - 7)(√5 - 7) in simplest form.

Solution

The given expression is:

(57)(57)(\sqrt{5} - 7)(\sqrt{5} - 7)

This is a binomial multiplication of the form (ab)(ab)(a - b)(a - b), which can be expanded using the formula for a perfect square trinomial:

(ab)2=a22ab+b2(a - b)^2 = a^2 - 2ab + b^2

Here, a=5a = \sqrt{5} and b=7b = 7. Let's expand it step by step:

  1. Square the first term: a2=(5)2=5a^2 = (\sqrt{5})^2 = 5

  2. Multiply the two terms and then double the result: 2ab=2(5)(7)=145-2ab = -2(\sqrt{5})(7) = -14\sqrt{5}

  3. Square the second term: b2=72=49b^2 = 7^2 = 49

Now, combine all the terms:

(57)2=5145+49(\sqrt{5} - 7)^2 = 5 - 14\sqrt{5} + 49

Simplify:

5+49145=541455 + 49 - 14\sqrt{5} = 54 - 14\sqrt{5}

Thus, the product (57)(57)(\sqrt{5} - 7)(\sqrt{5} - 7) simplifies to:

5414554 - 14\sqrt{5}

Would you like more details on any step, or do you have any questions?

Here are 5 related questions:

  1. How would you expand (23)(23)(\sqrt{2} - 3)(\sqrt{2} - 3)?
  2. Can you explain how the perfect square trinomial formula is derived?
  3. How do we handle square roots when simplifying expressions?
  4. What is the difference between expanding a binomial and factoring it?
  5. How can we verify the result using another method?

Tip: When expanding binomials, it's helpful to memorize the perfect square formula for quick simplification.

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Math Problem Analysis

Mathematical Concepts

Algebra
Binomial Expansion
Perfect Square Trinomial

Formulas

(a - b)^2 = a^2 - 2ab + b^2

Theorems

Perfect Square Trinomial Theorem

Suitable Grade Level

Grades 8-10