Squared problem

This topic has expert replies
Source: — Problem Solving |

User avatar
Master | Next Rank: 500 Posts
Posts: 472
Joined: Sun Mar 29, 2009 6:54 pm
Thanked: 56 times

by ssmiles08 » Sun May 17, 2009 8:17 pm
I would have not gotten that one either.

https://www.beatthegmat.com/square-root- ... 16615.html

I think that would explain it a lot better than I would have

User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

Re: Squared problem

by sanju09 » Mon May 18, 2009 5:15 am
Kasper Madsen wrote:Can someone please help me by explaining how you reach the answer in this question?
Recall: (a + b)^2 = a^2 + b^2 + 2 a b and (a + b) (a - b) = a^2 - b^2, and proceed like this:

[{√9 + (√80)} + {√9 – (√80)}]^2

= 9 + √80 + 9 – √80 + 2 × (81 – 80)

= 18 + 2

= 20.
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com