GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 03 Jun 2020, 19:59

### 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 = 3 is one solution to the equation x^2 + rx - 20 = 4, then r =

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 64225
If x = 3 is one solution to the equation x^2 + rx - 20 = 4, then r =  [#permalink]

### Show Tags

03 Aug 2019, 22:27
00:00

Difficulty:

15% (low)

Question Stats:

92% (00:40) correct 8% (00:53) wrong based on 25 sessions

### HideShow timer Statistics

If x = 3 is one solution to the equation $$x^2 + rx - 20 = 4$$, then r =

(A) -8

(B) -5

(C) -3

(D) 5

(E) 8

_________________
GMAT Club Legend
Joined: 11 Sep 2015
Posts: 4886
GMAT 1: 770 Q49 V46
Re: If x = 3 is one solution to the equation x^2 + rx - 20 = 4, then r =  [#permalink]

### Show Tags

05 Aug 2019, 09:13
Top Contributor
Bunuel wrote:
If x = 3 is one solution to the equation $$x^2 + rx - 20 = 4$$, then r =

(A) -8

(B) -5

(C) -3

(D) 5

(E) 8

If x = 3 is one solution to the equation x² + rx - 20 = 4, we can plug in x = 3 to get: 3² + r(3) - 20 = 4
Simplify: 9 + 3r - 20 = 4
Simplify: 3r - 11 = 4
Add 11 to both sides: 3r = 15
Solve: r = 15/3 = 5

Cheers,
Brent
_________________
Test confidently with gmatprepnow.com
Re: If x = 3 is one solution to the equation x^2 + rx - 20 = 4, then r =   [#permalink] 05 Aug 2019, 09:13