It is currently 30 May 2020, 19:54

### 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

# exponential problem

Author Message
TAGS:
Retired Moderator
Joined: 07 Jun 2014
Posts: 4806
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 162

Kudos [?]: 2669 [1] , given: 394

exponential problem [#permalink]  15 May 2018, 15:56
1
KUDOS
Expert's post
00:00

Question Stats:

95% (00:22) correct 5% (00:00) wrong based on 20 sessions
$$(\sqrt{5}+\sqrt{7})^2=$$

A. 12
B. $$12 + 2\sqrt{3}$$
C. $$12 + 4\sqrt{3}$$
D. $$12 + \sqrt{35}$$
E. $$12 + 2\sqrt{35}$$
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

GRE Instructor
Joined: 10 Apr 2015
Posts: 3264
Followers: 126

Kudos [?]: 3665 [1] , given: 62

Re: exponential problem [#permalink]  13 May 2019, 04:48
1
KUDOS
Expert's post
sandy wrote:
$$(\sqrt{5}+\sqrt{7})^2=$$

A. 12
B. $$12 + 2\sqrt{3}$$
C. $$12 + 4\sqrt{3}$$
D. $$12 + \sqrt{35}$$
E. $$12 + 2\sqrt{35}$$

Use FOIL to expand the product

Note: $$(\sqrt{x})(\sqrt{y})=\sqrt{xy}$$

So, $$(\sqrt{5}+\sqrt{7})^2=(\sqrt{5}+\sqrt{7})(\sqrt{5}+\sqrt{7})$$

$$=\sqrt{25}+\sqrt{35}+\sqrt{35}+\sqrt{49}$$

$$=5+2\sqrt{35}+7$$

$$=12+2\sqrt{35}$$

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com

Re: exponential problem   [#permalink] 13 May 2019, 04:48
Display posts from previous: Sort by