Skip to main content
Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 1, Problem 119

Perform the indicated operations. Assume all variables represent positive real numbers. (√2 + 3) (√2 - 3)

Verified step by step guidance
1
Recognize that the expression \((\sqrt{2} + 3)(\sqrt{2} - 3)\) is in the form of a product of conjugates, which follows the pattern \((a + b)(a - b) = a^2 - b^2\).
Identify \(a = \sqrt{2}\) and \(b = 3\) from the given expression.
Apply the difference of squares formula: \( (\sqrt{2})^2 - (3)^2 \).
Calculate each square separately: \((\sqrt{2})^2 = 2\) and \(3^2 = 9\).
Subtract the squares: \(2 - 9\) to simplify the expression further.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Product of Binomials

Multiplying two binomials involves applying the distributive property (FOIL method), where each term in the first binomial is multiplied by each term in the second. This process helps expand expressions like (a + b)(c + d) into a simplified polynomial.
Recommended video:
Guided course
03:41
Special Products - Cube Formulas

Difference of Squares

The expression (√2 + 3)(√2 - 3) fits the difference of squares pattern: (x + y)(x - y) = x² - y². Recognizing this pattern allows quick simplification by subtracting the square of the second term from the square of the first.
Recommended video:
06:24
Solving Quadratic Equations by Completing the Square

Simplifying Radicals

Simplifying radicals involves evaluating or rewriting square roots in simplest form. For example, (√2)² equals 2, which is essential when applying the difference of squares formula to expressions containing radicals.
Recommended video:
Guided course
5:48
Adding & Subtracting Unlike Radicals by Simplifying