NEW HERE? LEARN MORE
closeclose
Last visit was: 24 Apr 2024, 12:36 It is currently 24 Apr 2024, 12:36
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

For which of the following functions does f(x) = f(2 - x) ?

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
josemnz83
Manager
Manager
Joined: 01 Jul 2012
Posts: 78
Own Kudos [?]: 372 [45]
Given Kudos: 16
Location: United States
Schools: Mays '16 (A$) HBS '16 (D) Ross '16 (A$) Simon '16 (A) UVA Darden (WA) Tepper '16 (WL) Olin '16 (A$) Jones '16 (M$)
GMAT 1: 510 Q34 V28
GMAT 2: 580 Q35 V35
GMAT 3: 640 Q34 V44
GMAT 4: 690 Q43 V42
GPA: 3.61
WE:Education (Education)
Send PM
For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   11 Jul 2013, 10:06
2
Kudos
43
Bookmarks
00:00
A
B
C
D
E

Difficulty:

35% (medium)

Question Stats:

71% (01:40) correct 29% (01:54) wrong based on 978 sessions
Hide Show timer Statistics
For which of the following functions does \(f(x)=f(2-x)\)?

A. \(f(x)=x+2\)

B. \(f(x)=2x-x^2\)

C. \(f(x)=2-x\)

D. \(f(x)=(2-x)^2\)

E. \(f(x)=x^2\)

Show Spoiler
Answer choice C seems to work out if we plug in 1 for x. Did I do something wrong or must the function be true for all values? C does not work for a value of x=4?
f(x)=2-1=1
f(x)= 2-(2-x).....>2-(2-1).....>2-(1) = 1
ShowHide Answer
Official Answer
B
Most Helpful Reply
User avatar
blueseas
Current Student
Joined: 14 Dec 2012
Posts: 580
Own Kudos [?]: 4324 [10]
Given Kudos: 197
Location: India
Concentration: General Management, Operations
Schools: PGDM (GM) '15 (A)
GMAT 1: 700 Q50 V34
GPA: 3.6
Send PM
GMAT ToolKit User
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   11 Jul 2013, 10:17
6
Kudos
4
Bookmarks
josemnz83 wrote:
For which of the following functions does f(x)=f(2-x)?

A. f(x)=x+2
B. (fx)=2x-x^2
C. f(x)=2-x
D. f(x)=(2-x)^2
E. f(x)=x^2

Answer choice C seems to work out if we plug in 1 for x. Did I do something wrong or must the function be true for all values? C does not work for a value of x=4?
f(x)=2-1=1
f(x)= 2-(2-x).....>2-(2-1).....>2-(1) = 1


hi,

in all the option just put 2-x in place of x

A. f(x)=x+2===>f(2-x)=2-x+2=4-x==>not equal

B. (fx)=2x-x^2====>f(2-x)=2(2-x)-(2-x)^2=4-2x-x^2+4x-4=2x-x^2===>equal==correct

C. f(x)=2-x===>f(2-x)=2-(2-x)=x===>not equal

D. f(x)=(2-x)^2===>f(2-x)=(2-2+x)^2=x^2===>not equal

E. f(x)=x^2===>f(2-x)=(2-x)^2===>not equal

hence only B satisfies.

dont plug in this

hope it helps.
General Discussion
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92902
Own Kudos [?]: 618798 [3]
Given Kudos: 81588
Send PM
CAT Tests Forum Quiz Mode
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   11 Jul 2013, 10:20
1
Kudos
2
Bookmarks
Expert Reply
josemnz83 wrote:
For which of the following functions does f(x)=f(2-x)?

A. f(x)=x+2
B. (fx)=2x-x^2
C. f(x)=2-x
D. f(x)=(2-x)^2
E. f(x)=x^2

Answer choice C seems to work out if we plug in 1 for x. Did I do something wrong or must the function be true for all values? C does not work for a value of x=4?
f(x)=2-1=1
f(x)= 2-(2-x).....>2-(2-1).....>2-(1) = 1


If you plug x=1 then all options will work, since f(x)=f(1) and f(2-x)=f(1) too. For such kind of questions it's not a good idea to plug 0, -1 or 1.

Note that for plug-in method it might happen that for some particular number(s) more than one option may give "correct" answer. In this case just pick some other numbers and check again these "correct" options only.

Similar questions:
functions-problem-need-help-93184.html
for-which-of-the-following-functions-is-f-a-b-f-b-f-a-124491.html
let-the-function-g-a-b-f-a-f-b-143311.html
for-which-of-the-following-functions-f-is-f-x-f-1-x-for-85751.html

Hope it helps.
User avatar
Vinayprajapati
Manager
Manager
Joined: 24 May 2013
Posts: 56
Own Kudos [?]: 145 [0]
Given Kudos: 99
Send PM
GMAT ToolKit User
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   11 Jul 2013, 10:54
josemnz83 wrote:
For which of the following functions does f(x)=f(2-x)?

A. f(x)=x+2
B. (fx)=2x-x^2
C. f(x)=2-x
D. f(x)=(2-x)^2
E. f(x)=x^2

Answer choice C seems to work out if we plug in 1 for x. Did I do something wrong or must the function be true for all values? C does not work for a value of x=4?
f(x)=2-1=1
f(x)= 2-(2-x).....>2-(2-1).....>2-(1) = 1


If we plug x=0 then, f(0)=f(2)
A. F(0)= 2 and f(2)= 4
B. f(0)= 0 and f(2)= 0
C. F(0)= 2 and f(2)= 0
D. F(0)= 4 and f(2)= 0
E. f(0)= 0 and f(2)= 4

Hence b is the correct answer.
User avatar
veergmat
Manager
Manager
Joined: 08 Nov 2014
Posts: 62
Own Kudos [?]: 50 [3]
Given Kudos: 90
Location: India
GPA: 3
WE:Engineering (Manufacturing)
Send PM
GMAT ToolKit User
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   22 Dec 2014, 10:50
3
Kudos
It can be easily done in less than a minute simply by elimination or substitution method.

1) f(x)=x+2; for x=2-x , f(2-x)=4. Eliminated
2) f(x) = 2x-x^2; for x=2-x ,f(2-x)=2(2-x)-(2-x)^2 =(2-x)(2-2+x)=2x-x^2
3) f(x) = 2 - x; for x=2-x, f(2-x)=x . Eliminated
4) f(x)=(2-x)^2; for x=2-x, f(2-x)=(x)^2 . Eliminated
5) f(x)=x^2;for x=2-x, f(2-x)=(2-x)^2. Eliminated
User avatar
S
Nunuboy1994
Director
Director
Joined: 12 Nov 2016
Posts: 569
Own Kudos [?]: 118 [0]
Given Kudos: 167
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37
GRE 1: Q157 V158
GPA: 2.66
Send PM
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   23 Feb 2017, 19:34
What confuses my about this question, with answer "B," is an example in which you have f(2-3)

f(2-3)=-1

F(x)= 2(2-x)-(2-x)^2
F(2-3)= 2(2-3)-(2-3)^2
F(2-3)= 2(-1)-(-1)^2
F(2-3)= -2-1
F(2-3)= -3?

Maybe I'm tired or something but I keep coming to this conclusion.
avatar
B
SamBoyle
Intern
Intern
Joined: 31 Dec 2016
Posts: 46
Own Kudos [?]: 70 [1]
Given Kudos: 22
Send PM
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   18 Jul 2017, 17:01
1
Kudos
Nunuboy1994 wrote:
What confuses my about this question, with answer "B," is an example in which you have f(2-3)

f(2-3)=-1

F(x)= 2(2-x)-(2-x)^2
F(2-3)= 2(2-3)-(2-3)^2
F(2-3)= 2(-1)-(-1)^2
F(2-3)= -2-1
F(2-3)= -3?

Maybe I'm tired or something but I keep coming to this conclusion.


A good way to solve it is like this. Essentially the question is saying F(X) so everytime you see an X you're going to sub in the function 2-x. A good video explaining how functions work is here since most people here do a crappy job. https://www.youtube.com/watch?v=T6-Zdr5w_bE
Attachments

Function question 3.png
Function question 3.png [ 292.42 KiB | Viewed 46212 times ]

User avatar
G
testcracker
Manager
Manager
Joined: 24 Mar 2015
Status:love the club...
Posts: 220
Own Kudos [?]: 112 [1]
Given Kudos: 527
Send PM
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   11 Oct 2017, 13:59
1
Kudos
josemnz83 wrote:
For which of the following functions does f(x)=f(2-x)?

A. f(x)=x+2
B. (fx)=2x-x^2
C. f(x)=2-x
D. f(x)=(2-x)^2
E. f(x)=x^2

Answer choice C seems to work out if we plug in 1 for x. Did I do something wrong or must the function be true for all values? C does not work for a value of x=4?
f(x)=2-1=1
f(x)= 2-(2-x).....>2-(2-1).....>2-(1) = 1



hi

let f(0) = f(2)

B: f(0) = 0
f(2) = 4 - 4 = 0

so f(0)= f(2)
B is the answer

thanks
User avatar
G
KanishkM
Director
Director
Joined: 09 Mar 2018
Posts: 783
Own Kudos [?]: 453 [1]
Given Kudos: 123
Location: India
Schools: DeGroote'21 Desautels '21 NUS '21
Send PM
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   11 Jan 2019, 22:03
1
Bookmarks
josemnz83 wrote:
For which of the following functions does f(x)=f(2-x)?

A. f(x)=x+2
B. (fx)=2x-x^2
C. f(x)=2-x
D. f(x)=(2-x)^2
E. f(x)=x^2


A. f(x)=x+2
f(2-x) = 2-x+2, Not equal

B. f(x)=2x-x^2
f(2-x) = 2*(2-x) - (2-x)^2 = 4-2x- [ 4 + x^2 - 4x] = 2x-x^2

C. f(x)=2-x
f(2-x) = 2-2+x = x, Not equal

D. f(x)=(2-x)^2
f(2-x)= (2-2-x)^2 , Not equal

E. f(x)=x^2
f(2-x) = (2-x)^2, Not equal

Answer B
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32652
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink] New post   18 Mar 2024, 14:03
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.
GMAT Club Bot
gmatclubot
Re: For which of the following functions does f(x) = f(2 - x) ? [#permalink]
18 Mar 2024, 14:03
Moderators:
Bunuel
Math Expert
92902 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions