Last visit was: 22 Apr 2026, 21:46 It is currently 22 Apr 2026, 21:46
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,760
Own Kudos:
810,694
 [7]
Given Kudos: 105,845
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,760
Kudos: 810,694
 [7]
Kudos
Add Kudos
7
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,760
Own Kudos:
810,694
 [3]
Given Kudos: 105,845
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,760
Kudos: 810,694
 [3]
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
gmatbd
Joined: 03 Jan 2017
Last visit: 15 Jun 2025
Posts: 17
Own Kudos:
Given Kudos: 23
Posts: 17
Kudos: 1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,760
Own Kudos:
810,694
 [2]
Given Kudos: 105,845
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,760
Kudos: 810,694
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
gmatbd
I did not quite understand the solution. Case 3 isn't clear. Is it possible to elaborate the concept used here?
Sure! Let’s break down Case 3 in simpler terms.

We are given an equation of the form:

\((x^2 - 5x + 5)^{(x^2 + 8x)} = 1\)

This equation equals 1 in three situations:

  1. The base is 1: because 1^anything = 1
  2. The exponent is 0: because any non-zero number raised to the 0th power is 1
  3. The base is -1 and the exponent is even: because (-1)^even = 1

Now, focusing on Case 3: base is -1 and exponent is even

We want to find x such that the base, \(x^2 - 5x + 5\), is -1:

\(x^2 - 5x + 5 = -1\)
\((x - 2)(x - 3) = 0\)
\(x = 2 \) or \(x = 3\)

Now check whether the exponent, \(x^2 + 8x\), is even for any of these value of x:

  • x = 2 → \(x^2 + 8x = 4 + 16 = 20\) → even → valid
  • x = 3 → \(x^2 + 8x = 9 + 24 = 33\) → odd → invalid

So only x = 2 satisfies Case 3, meaning if x = 2, then the base, \(x^2 - 5x + 5\), is -1 and the exponent, \(x^2 + 8x\), is even, giving (-1)^even = 1.
Moderators:
Math Expert
109754 posts
Founder
43153 posts