praetorian123 wrote:

akamai, i have a question:

Did the others, including me ignore the negative value of the sqrt root here?

Example

4 + sqrt (16) ....this would be 8 isnt it?

but sqrt(16) = - 4 too...

Do we always take the positive value of the sqrt root in "expressions", unless otherwise mentioned.

thanks

praetorian

In the gmat, the square root sign signifies positive square root. HOWEVER, since I squared an expression in one of the steps in my solution, I no longer can claim the square root to be positive, i.e., I cannot say if x = -2 I cannot say since x^2 = 4, x = sqrt(x^2) = 2.

Going back to my solution, I would have to notice that the answer must be negative, then choose the correct root.

_________________

Best,

AkamaiBrah

Former Senior Instructor, Manhattan GMAT and VeritasPrep

Vice President, Midtown NYC Investment Bank, Structured Finance IT

MFE, Haas School of Business, UC Berkeley, Class of 2005

MBA, Anderson School of Management, UCLA, Class of 1993