Have questions about your preparation or an upcoming test? Need help modifying the Study Plan to meet your unique needs? No problem. Just book a Skype meeting with Brent to discuss these and any other questions you may have.

- Video Course
- Video Course Overview
- General GMAT Strategies - 7 videos (free)
- Data Sufficiency - 16 videos (free)
- Arithmetic - 38 videos
- Powers and Roots - 36 videos
- Algebra and Equation Solving - 73 videos
- Word Problems - 48 videos
- Geometry - 42 videos
- Integer Properties - 38 videos
- Statistics - 20 videos
- Counting - 27 videos
- Probability - 23 videos
- Analytical Writing Assessment - 5 videos (free)
- Reading Comprehension - 10 videos (free)
- Critical Reasoning - 38 videos
- Sentence Correction - 70 videos
- Integrated Reasoning - 17 videos

- Study Guide
- About
- Office Hours
- Extras
- Prices

## Comment on

Other Roots## You say a root will have at

-Yvonne

## When it comes to root

When it comes to root notation involving even roots (e.g.m square root, 4th root, 6th root, 8th root, etc.), the root NOTATION tells us to take only the positive root.

## So on the gmat test, will is

## Yes, most definitely.

Yes, most definitely.

## Reinforcement activities

## Thanks for the heads up,

Thanks for the heads up, BalysLTU!

I have removed one of the links.

Cheers,

Brent

## Hi Brent,

Could you solve this qs - https://gmatclub.com/forum/if-k-is-a-positive-integer-is-k-a-prime-number-96118.html

## Here's my full solution:

Here's my full solution: https://gmatclub.com/forum/if-k-is-a-positive-integer-is-k-a-prime-numbe...

## Why is even root of a

Isn't (-5)^4 also 625?

## Great question!!

Great question!!

Consider √9

There are two values that, when squared, result in 9.

Those two values are 3 and -3.

As you can imagine, it would be confusing for √9 to have more than one value.

For example, if I told you that x = √25, you wouldn't know whether x = 5 or x = -5.

So, mathematicians came up with the following construct:

√k = the POSITIVE value that, when squared, equals k, and -√k = the NEGATIVE value that, when squared, equals k.

That way, we can represent the positive square root one way, I represent the negative square root another (different) way

So, it all comes down to NOTATION.

We'll use √k to represent the POSITIVE square root of k, and we'll use -√k to represent the NEGATIVE square root of k.

Some examples:

√49 = 7

-√81 = -9

-√100 = -10

√16 = 4

This construct applies to all even roots.

For example, ∜16 = 2, and -∜16 = -2

Likewise, ∜625 = 5, and -∜625 = -5

Does that help?