Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 26 May 2017, 10:32

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

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

Author Message
TAGS:

### Hide Tags

Manager
Joined: 01 Jul 2012
Posts: 84
Location: United States
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)
Followers: 13

Kudos [?]: 130 [2] , given: 16

For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

11 Jul 2013, 10:06
2
KUDOS
4
This post was
BOOKMARKED
00:00

Difficulty:

35% (medium)

Question Stats:

64% (02:12) correct 36% (01:28) wrong based on 286 sessions

### HideShow timer Statistics

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
[Reveal] Spoiler: OA
Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GMAT 1: 700 Q50 V34
GPA: 3.6
Followers: 64

Kudos [?]: 1401 [3] , given: 197

Re: For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

11 Jul 2013, 10:17
3
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,

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.
_________________

When you want to succeed as bad as you want to breathe ...then you will be successfull....

GIVE VALUE TO OFFICIAL QUESTIONS...

learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmat-analytical-writing-assessment

Math Expert
Joined: 02 Sep 2009
Posts: 38908
Followers: 7739

Kudos [?]: 106218 [1] , given: 11613

Re: For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

11 Jul 2013, 10:20
1
KUDOS
Expert's post
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.
_________________
Manager
Joined: 24 May 2013
Posts: 86
Followers: 0

Kudos [?]: 26 [0], given: 99

Re: For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

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.
Manager
Joined: 08 Nov 2014
Posts: 93
Location: India
GPA: 3
WE: Engineering (Manufacturing)
Followers: 0

Kudos [?]: 15 [1] , given: 90

Re: For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

22 Dec 2014, 10:50
1
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
_________________

"Arise, Awake and Stop not till the goal is reached"

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15463
Followers: 649

Kudos [?]: 209 [0], given: 0

Re: For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

14 Feb 2017, 16:25
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.
_________________
Manager
Joined: 12 Nov 2016
Posts: 195
Followers: 0

Kudos [?]: 7 [0], given: 135

Re: For which of the following functions does f(x)=f(2-x)? [#permalink]

### Show Tags

23 Feb 2017, 19:34

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.
Re: For which of the following functions does f(x)=f(2-x)?   [#permalink] 23 Feb 2017, 19:34
Similar topics Replies Last post
Similar
Topics:
11 For which of the following functions does f(x) = f(1/x), given that x 7 01 Oct 2016, 12:00
14 For which of the following functions does f(−x)=−f(x) for all real num 6 31 Mar 2016, 03:51
16 Which of the following functions does not intersect with y = 3x^2 + 2x 6 08 Mar 2017, 12:56
7 Among the following functions, for which one is 8 14 Nov 2015, 13:32
253 For which of the following functions f is f(x)=f(1-x) for 33 30 Mar 2017, 16:24
Display posts from previous: Sort by