GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 16 Feb 2019, 16:21

### 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 February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Algebra Webinar

February 17, 2019

February 17, 2019

07:00 AM PST

09:00 AM PST

Attend this Free Algebra Webinar and learn how to master Inequalities and Absolute Value problems on GMAT.
• ### Free GMAT Strategy Webinar

February 16, 2019

February 16, 2019

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 52902
If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?  [#permalink]

### Show Tags

01 Oct 2018, 22:14
00:00

Difficulty:

55% (hard)

Question Stats:

44% (01:55) correct 56% (02:37) wrong based on 35 sessions

### HideShow timer Statistics

If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?

(A) 0
(B) 1
(C) 2
(D) 3
(E) 4

_________________
Director
Joined: 31 Jul 2017
Posts: 518
Location: Malaysia
GMAT 1: 700 Q50 V33
GPA: 3.95
WE: Consulting (Energy and Utilities)
Re: If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?  [#permalink]

### Show Tags

01 Oct 2018, 22:24
Bunuel wrote:
If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?

(A) 0
(B) 1
(C) 2
(D) 3
(E) 4

3f(x) + 2f(−x) = 5x − 10
2f(x) + 3f(-x) = -5x - 10

9f(x) + 6f(-x) = 15x - 30
4f(x) + 6f(-x) = -10x - 20

Subtract the above two equation -

5f(x) = 25x - 10
f(x) = 5x - 2
f(1) = 3

Hence, D.
_________________

If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!

##### General Discussion
Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3340
Location: India
GPA: 3.12
Re: If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?  [#permalink]

### Show Tags

01 Oct 2018, 22:50
2
1
Bunuel wrote:
If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?

(A) 0
(B) 1
(C) 2
(D) 3
(E) 4

If $$x=1$$, the equation becomes $$3f(1) + 2f(-1) = 5 - 10 = -5$$ -> (1)

If $$x=-1$$, the equation becomes $$3f(-1) + 2f(1) = -5 - 10 = -15$$ -> (2)

3*(1) - 2*(2) -> $$9f(1) - 4f(1) = -15 + 30 = 15$$ -> $$5f(1) = 15$$

Therefore, the value of f(1) = $$\frac{15}{5}$$ = 3(Option D)
_________________

You've got what it takes, but it will take everything you've got

Re: If 3f(x) + 2f(−x) = 5x − 10, what is the value of f (1)?   [#permalink] 01 Oct 2018, 22:50
Display posts from previous: Sort by