Last visit was: 31 Aug 2026, 23:18 It is currently 31 Aug 2026, 23:18
Home
Messages
Tests
Schools
Events
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
Back to Forum
Create Topic
505-555 (Easy)|   Algebra|      
avatar
malkov
avatar
Joined: 05 May 2012
Last visit: 02 Jun 2012
Posts: 11
Own Kudos:
65
 [9]
Given Kudos: 17
Posts: 11
Kudos: 65
 [9]
3x^2 + 2x - 8 = 13 May 2012, 22:53
2
Kudos
Add Kudos
7
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

15% (low)

Question Stats:

77% (01:07) correct 23% (01:27) wrong based on 497 sessions

History

Date
Time
Result
Not Attempted Yet
3x^2 + 2x - 8 =

A. (3x-4)(x-2)
B. (3x-4)(x+2)
C. (3x-4)(x-2)
D. (3x-2)(x+4)
E. none of above
ShowHide Answer
Official Answer
B
User avatar
GyanOne
User avatar
Joined: 24 Jul 2011
Last visit: 31 Aug 2026
Posts: 3,436
Own Kudos:
1,765
 [2]
Given Kudos: 35
Status: World Rank #4 MBA Admissions Consultant
Expert
Expert reply
Posts: 3,436
Kudos: 1,765
 [2]
3x^2 + 2x - 8 = 13 May 2012, 23:15
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
3x^2 + 2x - 8
= 3x^2 + 6x - 4x - 8
= 3x (x + 2) - 4 (x+2)
= (3x-4) (x+2)

Option B
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 31 Aug 2026
Posts: 113,004
Own Kudos:
838,242
Given Kudos: 111,243
Products:
GMAT Club Tests
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 113,004
Kudos: 838,242
3x^2 + 2x - 8 = 14 May 2012, 00:09
Kudos
Add Kudos
Bookmarks
Bookmark this Post
malkov
3x^2 + 2x - 8 =

A. (3x-4)(x-2)
B. (3x-4)(x+2)
C. (3x-4)(x-2)
D. (3x-2)(x+4)
E. none of above
Show more

Solving and Factoring Quadratics:
https://www.purplemath.com/modules/solvquad.htm
https://www.purplemath.com/modules/factquad.htm

Hope it helps.
User avatar
LalaB
User avatar
Current Student
Joined: 23 Oct 2010
Last visit: 17 Jul 2016
Posts: 226
Own Kudos:
1,427
 [1]
Given Kudos: 73
Location: Azerbaijan
Concentration: Finance
Schools: HEC '15 (A)
GMAT 1: 690 Q47 V38
Schools: HEC '15 (A)
GMAT 1: 690 Q47 V38
Posts: 226
Kudos: 1,427
 [1]
3x^2 + 2x - 8 = 14 May 2012, 01:05
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
3x^2 + 2x - 8

X1*X2=-8/3
X1+X2=-2/3

Only option B satisfies these parameters
User avatar
shasadou
User avatar
Joined: 12 Aug 2015
Last visit: 24 Nov 2022
Posts: 219
Own Kudos:
3,216
 [1]
Given Kudos: 1,475
Concentration: General Management, Operations
Schools: Johnson '18 (WL) Duke '18 (M) Tuck '18 (D)
GMAT 1: 640 Q40 V37
GMAT 2: 650 Q43 V36
GMAT 3: 600 Q47 V27
GPA: 3.3
WE:Management Consulting (Consulting)
Schools: Johnson '18 (WL) Duke '18 (M) Tuck '18 (D)
GMAT 3: 600 Q47 V27
Posts: 219
Kudos: 3,216
 [1]
3x^2 + 2x - 8 = 21 Jan 2016, 07:11
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
1. just open the brackets. A is out, B is in. 30 secs.

2. factoring box

a. 3x^2 + 2x - 8 -> mulptiply a and c = 3*-8 = -24
b. factors of -24 that add up to b (i.e. 2) are 6 and -4 (note that the larger factor should be positive because b is positive, one of the factors is negative)
c. arrange the box as below and find common factors in the 2 vertical and 2 horizontal lines. form equation. of (3x-4)(x+2)
Attachments

box.jpg
box.jpg [ 7.22 KiB | Viewed 10320 times ]

avatar
Peachie
avatar
Joined: 15 Feb 2019
Last visit: 22 Oct 2019
Posts: 12
Own Kudos:
5
Given Kudos: 17
Posts: 12
Kudos: 5
3x^2 + 2x - 8 = 04 Apr 2019, 06:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I used quadratic equation in solving this
3x^2+2x-8=
X=-b+/- sqrt b^2-4ac/2a
Where a =3, b=2, And c=-8
X=-2+/-sqrt 2^2-4(3)(-8)/2(3)
X=-2+/-sqrt 4+96/6
X=-2+/-sqrt100/6=-2+/-10/6
X=-2+10/6 or X=-2-10/6
X=8/6=4/3 or X=-12/6=-2
Therefore X=4/3 or -2
X=4/3= 3x=4, 3x-4=0
X=-2, X+2=0
So we have 3x-4=0 or x+2=0
Final answer (3x-4)(x+2)
Answer is B

Posted from my mobile device
avatar
Peachie
avatar
Joined: 15 Feb 2019
Last visit: 22 Oct 2019
Posts: 12
Own Kudos:
5
 [1]
Given Kudos: 17
Posts: 12
Kudos: 5
 [1]
3x^2 + 2x - 8 = 04 Apr 2019, 06:27
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I used quadratic equation in solving this
3x^2+2x-8=
X=-b+/- sqrt b^2-4ac/2a
Where a =3, b=2, And c=-8
X=-2+/-sqrt 2^2-4(3)(-8)/2(3)
X=-2+/-sqrt 4+96/6
X=-2+/-sqrt100/6=-2+/-10/6
X=-2+10/6 or X=-2-10/6
X=8/6=4/3 or X=-12/6=-2
Therefore X=4/3 or -2
X=4/3= 3x=4, 3x-4=0
X=-2, X+2=0
So we have 3x-4=0 or x+2=0
Final answer (3x-4)(x+2)
Answer is B

Posted from my mobile device
Attachments

20190404_142712.jpg
20190404_142712.jpg [ 937.92 KiB | Viewed 6882 times ]

User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 31 Aug 2026
Posts: 22,701
Own Kudos:
26,917
 [1]
Given Kudos: 302
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: 22,701
Kudos: 26,917
 [1]
3x^2 + 2x - 8 = 07 Apr 2019, 18:43
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
malkov
3x^2 + 2x - 8 =

A. (3x-4)(x-2)
B. (3x-4)(x+2)
C. (3x-4)(x-2)
D. (3x-2)(x+4)
E. none of above
Show more

Factoring the given quadratic expression, we have:

(3x - 4)(x + 2)

Answer: B
User avatar
Ayeka
User avatar
Joined: 26 May 2024
Last visit: 31 Aug 2026
Posts: 538
Own Kudos:
406
Given Kudos: 169
Location: India
Schools: ISB
GPA: 4.2
Products:
GMAT Club Tests
Schools: ISB
Posts: 538
Kudos: 406
3x^2 + 2x - 8 = 17 Sep 2024, 09:25
Kudos
Add Kudos
Bookmarks
Bookmark this Post
3x^2+2x-8=?
3x^2+6x-4x-8
3x(x+2)-4(x+2)
(3x-4)(x+2)

Answer: B

Posted from my mobile device
Moderator:
Bunuel
Math Expert
113004 posts