If xy+z=x(y+z), which of the following must be true? 1) : PS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 20 Jan 2017, 18:48

### 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

# Events & Promotions

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

# If xy+z=x(y+z), which of the following must be true? 1)

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Senior Manager
Joined: 08 Jun 2004
Posts: 497
Location: Europe
Followers: 1

Kudos [?]: 72 [0], given: 0

If xy+z=x(y+z), which of the following must be true? 1) [#permalink]

### Show Tags

04 Jul 2006, 02:10
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 3 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If xy+z=x(y+z), which of the following must be true?

1) x=0, z=0
2) x=1, y=1
3) y=1, z=0
4) x=1, y=0
5) x=1, z=0

OA will follow.
SVP
Joined: 30 Mar 2006
Posts: 1737
Followers: 1

Kudos [?]: 78 [0], given: 0

Re: PS: xy+z=x(y+z) [#permalink]

### Show Tags

04 Jul 2006, 02:55
M8 wrote:
If xy+z=x(y+z), which of the following must be true?

1) x=0, z=0
2) x=1, y=1
3) y=1, z=0
4) x=1, y=0
5) x=1, z=0

OA will follow.

4 ?

Am I wrong or does all the values satisfy?
Manager
Joined: 12 Apr 2006
Posts: 218
Location: India
Followers: 1

Kudos [?]: 28 [0], given: 17

### Show Tags

04 Jul 2006, 04:56
xy+z=x(y+z) => xy+z=xy+xz => xz - z = 0

=> z(x-1) = 0 => z=0, x=1

Hence 5
Intern
Joined: 05 Nov 2005
Posts: 33
Location: London
Followers: 0

Kudos [?]: 1 [0], given: 0

### Show Tags

04 Jul 2006, 05:02
xy + z = xy + xz

xy 's cancel out

z = xz
xz - z = 0
z(x-1) = 0

z = 0, x = 1

(5)
_________________

I am only one; but I am still one. I cannot do everything, but still I can do something. I will not refuse to do the something I can do.
- Helen Keller

VP
Joined: 25 Nov 2004
Posts: 1493
Followers: 7

Kudos [?]: 98 [0], given: 0

Re: PS: xy+z=x(y+z) [#permalink]

### Show Tags

04 Jul 2006, 07:33
M8 wrote:
If xy+z=x(y+z), which of the following must be true?

1) x=0, z=0
2) x=1, y=1
3) y=1, z=0
4) x=1, y=0
5) x=1, z=0

OA will follow.

xy + z = x (y + z)
xy + z = xy + xz
z = xz
xz - z = 0
z (x - 1) = 0
z = 0, x = 1

arrived at E.

however any value for x and y with z = 0 satisfy the eq xy + z = x (y + z). therefore, the question is not properly structured.
Intern
Joined: 23 Jun 2006
Posts: 26
Followers: 0

Kudos [?]: 4 [0], given: 0

### Show Tags

04 Jul 2006, 09:12
I don't think this question was written accurately.

You can deduce the equation to:

xy+ z = xy + xz --> thus y cancels out and its value doesn't matter

z = xz --> thus it only matters that x must equal 1, if that is true z can have any value
Senior Manager
Joined: 08 Jun 2004
Posts: 497
Location: Europe
Followers: 1

Kudos [?]: 72 [0], given: 0

### Show Tags

04 Jul 2006, 23:49
OA is 'E'.
But I was really stuck between A and E guys. What do you think about 'A'?
This is GMATPrep question.
Intern
Joined: 13 Jul 2006
Posts: 1
Followers: 0

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

### Show Tags

13 Jul 2006, 22:22
z=xz -> x = 1
z can be anything
let's try x=1, y=1, z=1
xy+z = x(y+z)
(1)(1) + 1 = 1 (1+1)
2=2 .... z doesn't have to equal 0

This question is poorly written!
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5062
Location: Singapore
Followers: 30

Kudos [?]: 358 [0], given: 0

### Show Tags

13 Jul 2006, 23:34
xy+z = x(y+z)
xy+z = xy+xz
z-xz = 0
z(1-x) = 0

z = 0, x = 1
13 Jul 2006, 23:34
Display posts from previous: Sort by

# If xy+z=x(y+z), which of the following must be true? 1)

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.