Last visit was: 24 Apr 2026, 20:09 It is currently 24 Apr 2026, 20:09
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
User avatar
nikhilpoddar
User avatar
Joined: 14 Jan 2006
Last visit: 01 Aug 2017
Posts: 55
Own Kudos:
83
Given Kudos: 2
Schools:HKUST
Posts: 55
Kudos: 83
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 24 Sep 2008, 18:14
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
avatar
VinViswanathan
avatar
Joined: 12 Aug 2008
Last visit: 17 Feb 2009
Posts: 3
Posts: 3
Kudos: 0
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 24 Sep 2008, 21:09
Kudos
Add Kudos
Bookmarks
Bookmark this Post
f b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6

Am I missing a part of this question, or is my interpretation incorrect :

Substituting the values of d & b mentioned above:

X^2 + 6x+ c = (x+3)^2
x^2 + 6x + c = x^2 + 6x + 9

Therefore c = 9
User avatar
GMAT TIGER
User avatar
Joined: 29 Aug 2007
Last visit: 17 Aug 2011
Posts: 1,012
Own Kudos:
1,796
Given Kudos: 19
Posts: 1,012
Kudos: 1,796
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 24 Sep 2008, 21:46
Kudos
Add Kudos
Bookmarks
Bookmark this Post
nikhilpoddar
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?

(1) d = 3
(2) b = 6
Show more

x^2 + bx + c = (x + d)^2
x^2 + bx + c = x^2 + 2xd + d^2

1: if d = 3, then x^2 + bx + c = x^2 + 6x + 9
bx + c = 6x + 9
b should be 6 and c = 9. suff..

2: if b = 6, then x^2 + bx + c = x^2 + 2xd + d^2
6x + c = 2xd + d^2
x, c and d can have many values.
nsf.
A.
User avatar
FN
User avatar
Current Student
Joined: 28 Dec 2004
Last visit: 07 May 2012
Posts: 1,575
Own Kudos:
687
Given Kudos: 2
Location: New York City
Concentration: Social Enterprise
Schools:Wharton'11 HBS'12
Posts: 1,575
Kudos: 687
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 24 Sep 2008, 21:48
Kudos
Add Kudos
Bookmarks
Bookmark this Post
if b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6

1)x^2+bx+C= x^2+2dx+d^2

c=d^2 or 9...

2) 2dx=6x then d=3...c=d^2..9,,

i get D
User avatar
klb15
User avatar
Joined: 21 May 2008
Last visit: 15 Jun 2012
Posts: 64
Own Kudos:
5
Given Kudos: 4
Posts: 64
Kudos: 5
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 24 Sep 2008, 23:24
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The trick is to compare LIKE terms.
X^2 + BX + C = X^2 + 2DX + D^2

Therefore comparing:
B = 2D
C = D^2

Ans is A.
User avatar
Twoone
User avatar
Joined: 02 Sep 2008
Last visit: 25 Oct 2008
Posts: 17
Posts: 17
Kudos: 0
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 25 Sep 2008, 06:48
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I am also getting D.

It is sufficient with both statements.
User avatar
GMAT TIGER
User avatar
Joined: 29 Aug 2007
Last visit: 17 Aug 2011
Posts: 1,012
Own Kudos:
1,796
Given Kudos: 19
Posts: 1,012
Kudos: 1,796
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 26 Sep 2008, 21:34
Kudos
Add Kudos
Bookmarks
Bookmark this Post
GMAT TIGER
nikhilpoddar
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value of c?

(1) d = 3
(2) b = 6

x^2 + bx + c = (x + d)^2
x^2 + bx + c = x^2 + 2xd + d^2

1: if d = 3, then x^2 + bx + c = x^2 + 6x + 9
bx + c = 6x + 9
b should be 6 and c = 9. suff..

2: if b = 6, then x^2 + bx + c = x^2 + 2xd + d^2
6x + c = 2xd + d^2
x, c and d can have many values.
nsf.
A.
Show more

in 2, suppose if x = 2, and d = 3
6x + c = 2xd + d^2
6*2 + c = 2*2*3 + 9
c = 9

suppose if x = 1, and d = 10
6x + c = 2xd + d^2
6 + c = 2d + d^2
6 + c = 20+100
c = 114

again, suppose if x = 5, and d = 10
6x + c = 2xd + d^2
6*5 + c = 10*10 + 100
c = 170

so C varies with x and D. how is st. (2) suff?

I guess I am missing something. anybody?
User avatar
yezz
User avatar
Retired Moderator
Joined: 05 Jul 2006
Last visit: 26 Apr 2022
Posts: 830
Own Kudos:
1,687
Given Kudos: 49
Posts: 830
Kudos: 1,687
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 26 Sep 2008, 21:38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
nikhilpoddar
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6
Show more

from 1

x^2 + bx + c = = x^2 + 3x+9

thus c = 9

from 2

x^2 +6x + c = x^2 + dx+d^2

c = d^2 = 9.........suff

my answer is d
User avatar
x2suresh
User avatar
Joined: 07 Nov 2007
Last visit: 18 Aug 2012
Posts: 711
Own Kudos:
3,148
Given Kudos: 5
Location: New York
Posts: 711
Kudos: 3,148
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 26 Sep 2008, 21:46
Kudos
Add Kudos
Bookmarks
Bookmark this Post
nikhilpoddar
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6
Show more

x^2 + bx + c = (x + d)^2
= x^2+2dx+d^2

b=2d
c=d^2

1) d = 3 -->c=d^2=9

suffcient
2) b=6 --> d=b/2=3 --> c=9
suffcieint

Ans D
User avatar
leonidas
User avatar
Joined: 29 Mar 2008
Last visit: 03 Aug 2009
Posts: 215
Own Kudos:
366
Posts: 215
Kudos: 366
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 26 Sep 2008, 21:57
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think everyone agrees that ST1 is sufficient.

Using ST2:
When b=6,
=> x^2+6x+c=x^2+2dx+d^2
=> c=x(2d-6) + d^2.

Since the stem says that c is a constant, it is possible when the constant c=d^2, i.e when 2d=6 => d=3
Since, c=d^2 => c=9

Hence (D)



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!