Flash card

[tuichats]

I saw this on one of the flash cards for number properties"WE ARE NOT ALLOWED TO TAKE AN EVEN ROOT OF A -VE # THEREFORE X MUST BE POSITIVE."
Can we take a odd root of a negative # then?
Thanks!

[messi10]

Hi tuichats,

Yes, I think odd roots are ok because odd roots preserve the sign.

cube root of 8 is 2 and cube root of -8 is -2
-2 x -2 x -2 = -8

However, for even roots of negative numbers we have to use the concept to an imaginary number, which is outside the scope of GMAT

Regards

Sunil

[jnelson0612]

Once again, Sunil is correct. :-)

[tuichats]

Thanks Guys! This totally makes sense..

[RonPurewal]

Thanks Guys! This totally makes sense..

glad it helped.