Please refer to the problem attached as an image. Question: Should we assume that only positive values will result from a square root? For instance, if we assume x = 1, then Sq root (x) = sq. root (1) = +1 or -1. In this case, the correct answer to the above problem could be (A) also. Please provide some insights.

euro wrote: Please refer to the problem attached as an image. Question: Should we assume that only positive values will result from a square root? For instance, if we assume x = 1, then Sq root (x) = sq. root (1) = +1 or -1. In this case, the correct answer to the above problem could be (A) also. Please provide some insights. When the GMAT writers use the square root symbol √, they mean the positive root only. √4 = 2. √9 = 3. √x means the positive square root of x. However, we when we solve by taking the square root, we have to account for the both the positive and negative roots: x^2 = 16 x = 4 or -4. Clear?

euro wrote: Please refer to the problem attached as an image. Question: Should we assume that only positive values will result from a square root? For instance, if we assume x = 1, then Sq root (x) = sq. root (1) = +1 or -1. In this case, the correct answer to the above problem could be (A) also. Please provide some insights. I think if you have to choose a side. If u are taking -ve part then u have to consider all -ve parts. Doing so u will have a real answer if u choose -ve 1.

This was a secret to me up until now. So, just to rephrase what you explained: if we (test-takers) perform a square root operation during any of our calculations, then we have to assume both +ve and -ve values; if GMAT uses a *square root sign* in one of its problems, then we have to consider ONLY the +ve values resulting from such a square root.

euro wrote:This was a secret to me up until now. So, just to rephrase what you explained: if we (test-takers) perform a square root operation during any of our calculations, then we have to assume both +ve and -ve values; if GMAT uses a *square root sign* in one of its problems, then we have to consider ONLY the +ve values resulting from such a square root. Its what I think but they can play around with are thought process so when confused in areas like this pick the concrete one. I will show you an example of over thinking. Just trust yourself https://www.beatthegmat.com/gmat-prep-no ... 68879.html

euro wrote:This was a secret to me up until now. So, just to rephrase what you explained: if we (test-takers) perform a square root operation during any of our calculations, then we have to assume both +ve and -ve values; if GMAT uses a *square root sign* in one of its problems, then we have to consider ONLY the +ve values resulting from such a square root. Correct!