GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 25 Sep 2018, 10:28

### 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

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

# If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to

Author Message
TAGS:

### Hide Tags

Retired Moderator
Joined: 28 May 2014
Posts: 528
GMAT 1: 730 Q49 V41
If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to  [#permalink]

### Show Tags

06 Oct 2017, 07:41
2
00:00

Difficulty:

15% (low)

Question Stats:

84% (01:34) correct 16% (02:24) wrong based on 73 sessions

### HideShow timer Statistics

If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to 0?

I. x^2 - 7x + 12
II. x^2 - 13x + 42
III. x^2 - 5x + 6

(a) I only
(b) II only
(c) III only
(d) II and III only
(e) I, II, and III

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 49496
Re: If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to  [#permalink]

### Show Tags

06 Oct 2017, 07:44
saswata4s wrote:
If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to 0?

I. x^2 - 7x + 12
II. x^2 - 13x + 42
III. x^2 - 5x + 6

(a) I only
(b) II only
(c) III only
(d) II and III only
(e) I, II, and III

This is a copy of the following OG question: https://gmatclub.com/forum/if-x-2-2x-15 ... 67001.html
_________________
Intern
Joined: 28 Dec 2010
Posts: 49
Re: If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to  [#permalink]

### Show Tags

08 Oct 2017, 03:31
Lets first find valid values of x
$$(x-7)(x+5) = 0 , and x> 0$$

This means x=7

Now look at
1. (x-3) (x-4)
2. (x-6) (x-7)
3. (x-2) (x-3)

Only Statement 2 would be 0.
B.
_________________

_________________________________________

Senior SC Moderator
Joined: 22 May 2016
Posts: 1981
If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to  [#permalink]

### Show Tags

08 Oct 2017, 04:31
saswata4s wrote:
If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to 0?

I. x^2 - 7x + 12
II. x^2 - 13x + 42
III. x^2 - 5x + 6

(a) I only
(b) II only
(c) III only
(d) II and III only
(e) I, II, and III

$$x^2 - 2x - 35 = 0$$
Find $$x$$

$$(x - 7)(x + 5)$$
$$x = 7$$ or $$x = -5$$
Prompt: $$x > 0$$, so $$x = 7$$

Either factor the expressions in the options, or plug $$x = 7$$ into them.

If you factor the expressions, one or both factors must be $$(x - 7)$$

Plugging in $$x = 7$$, looking for "which [option] must be equal to 0":

I. $$x^2 - 7x + 12$$
$$49 - 49 + 12 = 12$$ NO

II. $$x^2 - 13x + 42$$
$$49 - 91 + 42 = 0$$ YES

III. $$x^2 - 5x + 6$$
$$49 - 35 + 12 = 26$$ NO

Only Option II yields 0.

_________________

In the depths of winter, I finally learned
that within me there lay an invincible summer.

If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to &nbs [#permalink] 08 Oct 2017, 04:31
Display posts from previous: Sort by

# If x^2 - 2x - 35 = 0 and x>0, which of the following must be equal to

## Events & Promotions

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