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

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## Comment on

Big Exponents## I don't understand what this

## Are you familiar with Data

Are you familiar with Data Sufficiency question? If not, watch this video: https://www.gmatprepnow.com/module/gmat-data-sufficiency/video/1095

The question is asking "Is x positive?"

Our goal is to determine whether we can use either of the given statements to definitively answer the question ("Is x positive?")

## If I consider x=0 both the

## Keep in mind that 0^15 = 0,

Keep in mind that 0^15 = 0, and 0^16 = 0.

So, x = 0 does not satisfy the conditions in either statement.

For example, for statement 1, 0^15 is NOT greater than 0.

Likewise, for statement 2, 0^16 is NOT greater than 0.

## I'm confused about x^15>0

For example, if I use x=-2, x=2

isn't the answer as follows for statement 1:

for x=-2, -2^15>0, then -2^15 will be negative number based on the exponent taking the sign of the base? Wouldn't this make it insufficient because ->0 is wrong? Thank you!

## Statement 1 tells us that x

Statement 1 tells us that x^15 > 0

This means that x CANNOT equal -2, since (-2)^15 equals a negative value.

In fact, if x^15 > 0 then we can be certain that x is positive.

## Still very confusing.. If X

## "x can be literally any value

"x can be literally any value..."

This is true. However, the target question doesn't ask us to find the value of x; the target question asks us to determine whether or not x is POSITIVE

"...if we make X a negative number, it'll have to be a negative value with odd power making it LESS than 0"

Also true.

However, statement 1 tells us that x^15 is POSITIVE

In other words, Statement 1 tells us that x^ODD = POSITIVE

This means x must be POSITIVE

So, x CANNOT be negative.

"Wouldn't that make statement 1 insufficient if the number selected is a negative number will automatically make it a negative outcome making the statement false?"

KEY POINT: In a data sufficiency question, the statements are always TRUE.

So, when statement 1 tells us that x^15 is POSITIVE, we can be 100% certain that x^15 is POSITIVE.

If we accept this statement as true, what can we conclude about x?

It tells us that x must be positive (otherwise, that would contradict statement 1, which is 100% true).

ASIDE: Pretty much everyone struggles with DS with Data Sufficiency questions at first. You might want to spend some time reviewing the videos in the Data Sufficiency module (https://www.gmatprepnow.com/module/gmat-data-sufficiency) so that you have a solid understanding of this question type.

Cheers,

Brent

## nice question...

## In an earlier video in this

## Please see my reply to your

Please see my reply to your question above.

If you have any questions, please don't hesitate to ask.

Cheers,

Brent

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