Last visit was: 27 May 2024, 12:40 It is currently 27 May 2024, 12:40
Decision Tracker
My Rewards
Unanswered
Active Topics
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

If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
jlgdr
VP
VP
Joined: 06 Sep 2013
Posts: 1343
Own Kudos [?]: 2404 [4]
Given Kudos: 355
Concentration: Finance
Schools: Wharton '17 (A) HBS '17 (WA$)
Send PM
GMAT ToolKit User
If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   Updated on: 13 Oct 2013, 05:01
1
Kudos
3
Bookmarks
00:00
A
B
C
D
E

Difficulty:

15% (low)

Question Stats:

84% (01:38) correct 16% (02:21) wrong based on 173 sessions
Hide Show timer Statistics
If \(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\), then z=

(A) 2
(B) 1
(C) -1
(D) -2
(E) -3
ShowHide Answer
Official Answer
A

Originally posted by jlgdr on 11 Oct 2013, 17:10.
Last edited by jlgdr on 13 Oct 2013, 05:01, edited 3 times in total.
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 93489
Own Kudos [?]: 627189 [1]
Given Kudos: 81965
Send PM
CAT Tests Forum Quiz Mode
Re: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   11 Oct 2013, 17:29
1
Kudos
Expert Reply
jlgdr wrote:
If \(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\), then z=

(A) 2
(B) 1
(C) -1
(D) -2
(E) -3


I would solve this question by substituting the options but below is an algebraic approach if interested:

\(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\);

\(\frac{z^2-9+z^2-1}{(z-1)(z-3)}= 2\);

\(2z^2-10=2z^2-8z+6\);

\(8z=16\);

\(z=2\).

Answer: A.
User avatar
jlgdr
VP
VP
Joined: 06 Sep 2013
Posts: 1343
Own Kudos [?]: 2404 [0]
Given Kudos: 355
Concentration: Finance
Schools: Wharton '17 (A) HBS '17 (WA$)
Send PM
GMAT ToolKit User
Re: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   11 Oct 2013, 17:49
Bunuel wrote:
jlgdr wrote:
If \(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\), then z=

(A) 2
(B) 1
(C) -1
(D) -2
(E) -3


I would solve this question by substituting the options but below is an algebraic approach if interested:

\(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\);

\(\frac{z^2-9+z^2-1}{(z-1)(z-3)}= 2\);

\(2z^2-10=2z^2-8z+6\);

\(8z=16\);

\(z=2\).

Answer: A.


I agree, best approach is to sustitute. Now next question would be? Do we have a way to do a fast check and see which value to substitute first?
avatar
himang
Intern
Intern
Joined: 24 Apr 2013
Status:NOT READY TO GIVE UP
Posts: 19
Own Kudos [?]: 10 [1]
Given Kudos: 45
Location: India
Concentration: Strategy, Marketing
GMAT Date: 10-30-2013
WE:Engineering (Other)
Send PM
Re: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   12 Oct 2013, 22:16
1
Kudos
jlgdr wrote:
Bunuel wrote:
jlgdr wrote:
If \(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\), then z=

(A) 2
(B) 1
(C) -1
(D) -2
(E) -3


I would solve this question by substituting the options but below is an algebraic approach if interested:

\(\frac{z+3}{z-1}+\frac{z+1}{z-3} = 2\);

\(\frac{z^2-9+z^2-1}{(z-1)(z-3)}= 2\);

\(2z^2-10=2z^2-8z+6\);

\(8z=16\);

\(z=2\).

Answer: A.


I agree, best approach is to sustitute. Now next question would be? Do we have a way to do a fast check and see which value to substitute first?



I agree...OA is A someone kindly change the OA in the question...
User avatar
jlgdr
VP
VP
Joined: 06 Sep 2013
Posts: 1343
Own Kudos [?]: 2404 [0]
Given Kudos: 355
Concentration: Finance
Schools: Wharton '17 (A) HBS '17 (WA$)
Send PM
GMAT ToolKit User
Re: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   13 Oct 2013, 05:02
OA has been changed

Cheers

Posted from my mobile device
avatar
B
OptimusPrepJanielle
SVP
SVP
Joined: 06 Nov 2014
Posts: 1798
Own Kudos [?]: 1374 [0]
Given Kudos: 23
Send PM
Re: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   22 Jul 2015, 08:25
Expert Reply
If z+3z−1+z+1z−3=2, then z=

(A) 2
(B) 1
(C) -1
(D) -2
(E) -3
Attachments

Untitled.jpg
Untitled.jpg [ 42.26 KiB | Viewed 4886 times ]

avatar
noTh1ng
Manager
Manager
Joined: 07 Apr 2015
Posts: 128
Own Kudos [?]: 189 [1]
Given Kudos: 185
Send PM
If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   27 Jul 2015, 01:23
1
Kudos
OptimusPrepJanielle wrote:
If z+3z−1+z+1z−3=2, then z=

(A) 2
(B) 1
(C) -1
(D) -2
(E) -3


When you multiply with (z-1) and (z-3) in the first step, how does the denom. become (z-1)*(z-3)?
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 33241
Own Kudos [?]: 830 [0]
Given Kudos: 0
Send PM
Re: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink] If (z+3)/(z-1) + (z+1)/(z-3)=2, then z=   10 Nov 2023, 08:49
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: If (z+3)/(z-1) + (z+1)/(z-3)=2, then z= [#permalink]
10 Nov 2023, 08:49
Moderator:
Bunuel
Math Expert
93489 posts