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 22

Write each root using exponents and evaluate. - ∛-343

Verified step by step guidance
1
Recognize that the expression involves a cube root of a negative number: \(\sqrt[3]{-343}\).
Recall that the cube root of a number \(a\) can be written using exponents as \(a^{\frac{1}{3}}\).
Rewrite the expression using exponents: \((-343)^{\frac{1}{3}}\).
Note that \(343\) is a perfect cube since \$7^3 = 343\(, so \)-343 = -(7^3)$.
Use the property of exponents to simplify: \((-1 \times 7^3)^{\frac{1}{3}} = (-1)^{\frac{1}{3}} \times (7^3)^{\frac{1}{3}}\).

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.

Cube Roots and Radicals

The cube root of a number is a value that, when multiplied by itself three times, gives the original number. It is denoted as ∛a and can be positive or negative depending on the original number. For example, ∛-343 equals -7 because (-7)³ = -343.
Recommended video:
Guided course
05:20
Expanding Radicals

Exponential Notation for Roots

Roots can be expressed using fractional exponents, where the nth root of a number a is written as a^(1/n). For the cube root, ∛a is equivalent to a^(1/3). This notation allows the use of exponent rules to simplify and evaluate roots.
Recommended video:
02:20
Imaginary Roots with the Square Root Property

Evaluating Negative Bases with Odd Roots

When dealing with negative numbers under odd roots, such as cube roots, the result is also negative because an odd number of negative factors multiply to a negative product. This contrasts with even roots, which are not defined for negative bases in real numbers.
Recommended video:
05:02
Square Roots of Negative Numbers