Last visit was: 09 Jul 2025, 12:47 It is currently 09 Jul 2025, 12:47
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
shridhar786
Joined: 31 May 2018
Last visit: 08 Feb 2022
Posts: 325
Own Kudos:
1,684
 [23]
Given Kudos: 132
Location: United States
Concentration: Finance, Marketing
Posts: 325
Kudos: 1,684
 [23]
1
Kudos
Add Kudos
22
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
satya2029
Joined: 10 Dec 2017
Last visit: 09 Jul 2025
Posts: 231
Own Kudos:
241
 [6]
Given Kudos: 136
Location: India
Posts: 231
Kudos: 241
 [6]
2
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
General Discussion
User avatar
nick1816
User avatar
Retired Moderator
Joined: 19 Oct 2018
Last visit: 28 Jun 2025
Posts: 1,853
Own Kudos:
7,809
 [3]
Given Kudos: 707
Location: India
Posts: 1,853
Kudos: 7,809
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
User avatar
SiddharthR
Joined: 22 Oct 2018
Last visit: 20 Feb 2022
Posts: 85
Own Kudos:
35
 [1]
Given Kudos: 201
Location: United States (TX)
Concentration: Finance, Technology
GMAT 1: 590 Q42 V29
GMAT 2: 650 Q47 V33
GPA: 3.7
WE:Engineering (Consumer Electronics)
GMAT 2: 650 Q47 V33
Posts: 85
Kudos: 35
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
nick1816
The reflection of (x, y) across line x=0 is (-x, y)
The reflection of (x, y) across line y=0 is (x, -y)
The reflection of (x, y) across line y=x is (y, x)
The reflection of (x, y) across line y=-x is (-y, -x)
The reflection of (x, y) across line y=-3 is (x, -6-y)

D

shridhar786
The point R in the xy-plane with coordinates (–8, 3) is reflected over the line ll, giving the point R’ with coordinates (–3, 8). What is the equation of the line ll?

(A) x = 0

(B) y = 0

(C) y = x

(D) y = – x

(E) y = –3



I don't understand the following one "The reflection of (x, y) across line y=-3 is (x, -6-y)" How do you get this ?
User avatar
nick1816
User avatar
Retired Moderator
Joined: 19 Oct 2018
Last visit: 28 Jun 2025
Posts: 1,853
Own Kudos:
7,809
 [2]
Given Kudos: 707
Location: India
Posts: 1,853
Kudos: 7,809
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
SiddharthR
Attachment:
Untitled.png
Untitled.png [ 10.18 KiB | Viewed 4877 times ]

Distance of (x,y) from x-axis = y

Distance of y= -3 from x-axis = 3

Distance of (x,y) from y= -3 is equal to y+3

Since (x,y') is the reflection of the (x,y) wrt line y=-3, distance of (x,y') from y=-3 is equal to y+3.

Distance of (x,y') from x-axis = |y'| = y+3+y+3-y = 6+y

Since y'< 0, y' = -6-y
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 09 Jul 2025
Posts: 21,066
Own Kudos:
26,121
 [1]
Given Kudos: 296
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,066
Kudos: 26,121
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
shridhar786
The point R in the xy-plane with coordinates (–8, 3) is reflected over the line ll, giving the point R’ with coordinates (–3, 8). What is the equation of the line ll?

(A) x = 0

(B) y = 0

(C) y = x

(D) y = – x

(E) y = –3
Solution:

Recall that if a point is reflected over the line y = x, the image point will have the coordinates switched. Here, we see that not only have the coordinates of R’ been switched, but they are also negated. In that case, the line of reflection must be y = -x.

Answer: D
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,364
Own Kudos:
Posts: 37,364
Kudos: 1,010
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
102609 posts
PS Forum Moderator
682 posts