BrightChamps Logo
Hamburger Menu Icon for BrightChamps Website Navigation
Login
Creative Math Ideas Image
Live Math Learners Count Icon122 Learners

Last updated on May 26th, 2025

Math Whiteboard Illustration

Square Root of -128

Professor Greenline Explaining Math Concepts

If a number is multiplied by the same number, the result is a square. The inverse of the square is a square root. The square root is used in various fields, including vehicle design, finance, etc. Here, we will discuss the square root of -128.

Square Root of -128 for US Students
Professor Greenline from BrightChamps

What is the Square Root of -128?

The square root is the inverse of the square of the number. Since -128 is a negative number, it does not have a real square root. Instead, the square root of -128 is expressed in terms of imaginary numbers. In radical form, it is expressed as √-128 = √128 * i, where i is the imaginary unit. In exponential form, it can be written as (128)^(1/2) * i. Simplifying further, √128 = 8√2, so √-128 = 8√2 * i, which is an imaginary number.square root of minus 128

Professor Greenline from BrightChamps

Finding the Square Root of -128

Since -128 is a negative number, we use the concept of imaginary numbers to find its square root. The prime factorization method, long division method, and approximation method are not applicable for negative numbers in the context of real numbers. Instead, we find the square root of the absolute value and multiply it by i:

 

Step 1: Find the square root of the absolute value, 128.

 

Step 2: Include the imaginary unit i to represent the square root of -128.

Professor Greenline from BrightChamps

Square Root of 128 by Prime Factorization Method

To find the square root of 128, we use the prime factorization method.

 

Step 1: Find the prime factors of 128. Breaking it down, we get 2 x 2 x 2 x 2 x 2 x 2 x 2 = 2^7.

 

Step 2: Pair the prime factors. Since 128 is not a perfect square, we can pair the 2s: 2^7 = (2^3 * 2^3) * 2 = (8 * 8) * 2.

 

Step 3: The square root of 128 is 8√2. Therefore, the square root of -128 is 8√2 * i.

Professor Greenline from BrightChamps

Square Root of -128 by Imaginary Unit

To find the square root of a negative number like -128, we use the imaginary unit i, where i^2 = -1.

 

Step 1: Find the square root of the positive number 128, which is 8√2.

 

Step 2: Multiply the result by i to account for the negative sign. So the square root of -128 is 8√2 * i.

Professor Greenline from BrightChamps

Understanding Negative Square Roots

The concept of negative square roots involves imaginary numbers, as real numbers do not have square roots for negative values.

 

Step 1: Recognize that for any negative number, the square root involves i.

 

Step 2: Calculate the square root of the positive equivalent, and multiply by i. For example, √-128 = √128 * i = 8√2 * i.

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in the Square Root of -128

Students often make mistakes when dealing with square roots of negative numbers. Here are some common errors and how to avoid them.

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Forgetting the Imaginary Unit

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

A common mistake is forgetting to include the imaginary unit i when calculating square roots of negative numbers.

 

For example, √-128 should be expressed as 8√2 * i, not just 8√2.

Max from BrightChamps Saying "Hey"

Square Root of -128 Examples

Ray, the Character from BrightChamps Explaining Math Concepts
Max, the Girl Character from BrightChamps

Problem 1

Can you help Max find the square root of -128 in terms of imaginary numbers?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

The square root of -128 is 8√2 * i.

Explanation

First, find the square root of 128, which is 8√2.

Then, multiply by i to account for the negative sign: √-128 = 8√2 * i.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 2

If a complex number is given as √-128, what is its real and imaginary part?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

Real part: 0, Imaginary part: 8√2.

Explanation

The complex number √-128 can be expressed as 0 + 8√2 * i.

The real part is 0, and the imaginary part is 8√2.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 3

Calculate 2 times the square root of -128.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

16√2 * i

Explanation

First, find the square root of -128, which is 8√2 * i.

Then, multiply by 2: 2 * 8√2 * i = 16√2 * i.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 4

What is the square of the imaginary unit i?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

The square of i is -1.

Explanation

By definition, i is the imaginary unit, where i^2 = -1.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 5

How do you express √-128 in terms of a complex number?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

0 + 8√2 * i

Explanation

The square root of a negative number is expressed as an imaginary number. For √-128, it is 0 + 8√2 * i, where the real part is 0.

Max from BrightChamps Praising Clear Math Explanations
Ray Thinking Deeply About Math Problems

FAQ on Square Root of -128

1.What is √-128 in terms of imaginary numbers?

Math FAQ Answers Dropdown Arrow

2.Why can't we find a real square root of -128?

Math FAQ Answers Dropdown Arrow

3.How do you find the square root of a negative number?

Math FAQ Answers Dropdown Arrow

4.What is the principal square root of a negative number?

Math FAQ Answers Dropdown Arrow

5.Is √-128 a real number?

Math FAQ Answers Dropdown Arrow

6.How does learning Algebra help students in United States make better decisions in daily life?

Math FAQ Answers Dropdown Arrow

7.How can cultural or local activities in United States support learning Algebra topics such as Square Root of -128?

Math FAQ Answers Dropdown Arrow

8.How do technology and digital tools in United States support learning Algebra and Square Root of -128?

Math FAQ Answers Dropdown Arrow

9.Does learning Algebra support future career opportunities for students in United States?

Math FAQ Answers Dropdown Arrow
Professor Greenline from BrightChamps

Important Glossaries for the Square Root of -128

  • Square root: The square root is the inverse operation of squaring a number. For negative numbers, it involves imaginary numbers.
     
  • Imaginary number: An imaginary number is a number that can be expressed in the form of a real number multiplied by the imaginary unit i.
     
  • Imaginary unit: The imaginary unit i is defined such that i^2 = -1, used to express square roots of negative numbers.
     
  • Complex number: A complex number consists of a real part and an imaginary part, expressed as a + bi.
     
  • Absolute value: The absolute value of a number is its non-negative value, used when finding square roots of negative numbers.
Professor Greenline from BrightChamps

About BrightChamps in United States

At BrightChamps, we understand algebra is more than just symbols—it’s a gateway to endless possibilities! Our goal is to empower kids throughout the United States to master key math skills, like today’s topic on the Square Root of -128, with a special emphasis on understanding square roots—in an engaging, fun, and easy-to-grasp manner. Whether your child is calculating how fast a roller coaster zooms through Disney World, keeping track of scores during a Little League game, or budgeting their allowance for the latest gadgets, mastering algebra boosts their confidence to tackle everyday problems. Our hands-on lessons make learning both accessible and exciting. Since kids in the USA learn in diverse ways, we customize our methods to suit each learner’s style. From the lively streets of New York City to the sunny beaches of California, BrightChamps brings math alive, making it meaningful and enjoyable all across America. Let’s make square roots an exciting part of every child’s math adventure!
Math Teacher Background Image
Math Teacher Image

Jaskaran Singh Saluja

About the Author

Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.

Math Teacher Fun Facts Image
Max, the Girl Character from BrightChamps

Fun Fact

: He loves to play the quiz with kids through algebra to make kids love it.

INDONESIA - Axa Tower 45th floor, JL prof. Dr Satrio Kav. 18, Kel. Karet Kuningan, Kec. Setiabudi, Kota Adm. Jakarta Selatan, Prov. DKI Jakarta
INDIA - H.No. 8-2-699/1, SyNo. 346, Rd No. 12, Banjara Hills, Hyderabad, Telangana - 500034
SINGAPORE - 60 Paya Lebar Road #05-16, Paya Lebar Square, Singapore (409051)
USA - 251, Little Falls Drive, Wilmington, Delaware 19808
VIETNAM (Office 1) - Hung Vuong Building, 670 Ba Thang Hai, ward 14, district 10, Ho Chi Minh City
VIETNAM (Office 2) - 143 Nguyễn Thị Thập, Khu đô thị Him Lam, Quận 7, Thành phố Hồ Chí Minh 700000, Vietnam
Dubai - BrightChamps, 8W building 5th Floor, DAFZ, Dubai, United Arab Emirates
UK - Ground floor, Redwood House, Brotherswood Court, Almondsbury Business Park, Bristol, BS32 4QW, United Kingdom