Last visit was: 28 Dec 2024, 16:45 It is currently 28 Dec 2024, 16:45
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

Close

GRE Prep 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 GRE 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
PREVIOUS TOPIC
NEXT TOPIC

If f(x) = 2x^2 − 4 and g(x) = 2x, for what values of x will f(x) = g

Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

User avatar
D
GeminiHeat
GRE Prep Club Team Member
Joined: 20 Feb 2017
Posts: 2506
Own Kudos [?]: 3679 [2]
Given Kudos: 1053
GPA: 3.39
Send PM
If f(x) = 2x^2 − 4 and g(x) = 2x, for what values of x will f(x) = g [#permalink] New post   20 Feb 2021, 07:54
1
Expert Reply
1
Bookmarks
00:00

Question Stats:

73% (01:05) correct 26% (01:56) wrong based on 19 sessions

Hide Show timer Statistics

If \(f(x) = 2x^2 − 4\) and \(g(x) = 2x\), for what values of x will \(f(x)= g(x)\)?

A. x = {1, 2}

B. x = {−1, 2}

C. x = {−1, −2}

D. x = {1, −2}

E. x = {−1, 1}
ShowHide Answer
Official Answer
B
User avatar
D
KarunMendiratta
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Own Kudos [?]: 3274 [0]
Given Kudos: 172
Location: India
WE:Education (Education)
Send PM
If f(x) = 2x^2 − 4 and g(x) = 2x, for what values of x will f(x) = g [#permalink] New post   20 Feb 2021, 07:59
GeminiHeat wrote:
If \(f(x) = 2x^2 − 4\) and \(g(x) = 2x\), for what values of x will \(f(x)= g(x)\)?

A. x = {1, 2}

B. x = {−1, 2}

C. x = {−1, −2}

D. x = {1, −2}

E. x = {−1, 1}


\(f(x) = g(x)\)
\(2x^2 − 4 = 2x\)
\(x^2 − 2 = x\)
\(x^2 − 2x - 4 = 0\)
\((x - 2)(x + 1) = 0\)
i.e. \(x = 2\) or \(-1\)

Hence, option B
User avatar
G
BrushMyQuant
Moderator
Moderator
Joined: 02 Jan 2020
Status:GRE Quant Tutor
Posts: 1116
Own Kudos [?]: 975 [0]
Given Kudos: 9
Location: India
Concentration: General Management
Schools: XLRI Jamshedpur, India - Class of 2014
GMAT 1: 700 Q51 V31
GPA: 2.8
WE:Engineering (Computer Software)
Send PM
If f(x) = 2x^2 4 and g(x) = 2x, for what values of x will f(x) = g [#permalink] New post   03 Jul 2021, 03:46
Given that \(f(x) = 2x^2 − 4\) and \(g(x) = 2x\)

f(x) = g(x)
=> \(2x^2 − 4\) = 2x
=> \(2x^2\) - 2x - 4 = 0

Divide both the sides by 2 we get
=> \(x^2\) - x - 2 = 0
=> \(x^2\) + x - 2x - 2 = 0
=> x(x+1) - 2(x+1) = 0
=> (x+1) * (x-2) = 0
=> x = -1 or 2

So, Answer will be B
Hope it helps!

To learn more about Functions watch the following video

User avatar
G
HarishKumar
GRE Instructor
Joined: 24 Dec 2018
Posts: 1066
Own Kudos [?]: 1432 [1]
Given Kudos: 24
Send PM
If f(x) = 2x^2 4 and g(x) = 2x, for what values of x will f(x) = g [#permalink] New post   03 Sep 2023, 23:17
1
\(f(x) = 2x^2 -4\)
\(g(x) = 2x\)

if \(f(x) = g(x)\), then

\(2x^2-4 = 2x\)

\(2x^2- 2x -4 = 0\)

dividing throughout by \(2\), we get

\(x^2 - x -2 = 0\)

\(x^2 -2x +x -2 = 0\)

\(x(x-2) +1(x-2) = 0\)

\((x+1)(x-2) = 0\)

For \(x = -1\) and \(x = 2\), \(f(x)=g(x)\).

The answer is Choice B.
Prep Club for GRE Bot
gmatclubot
If f(x) = 2x^2 4 and g(x) = 2x, for what values of x will f(x) = g [#permalink]
03 Sep 2023, 23:17
Moderators:
adewale223
GRE Instructor
88 posts
bronaugust
GRE Forum Moderator
37 posts
BrushMyQuant
Moderator
1116 posts
VibhuAnurag
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

Partners

GRE Resources

www.ets.org/gre | About | Terms and Conditions and Privacy Policy | Prep Club for GRE Rules | Contact