If f(x) = x^n - a = 0, how many REAL roots does x have?
(1) a < 0
(2) n = 2k, where k is a positive integer
(1) a < 0
(2) n = 2k, where k is a positive integer
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x^n - a = 0 --> x= a^(1/n)austin wrote:If f(x) = x^n - a = 0, how many REAL roots does x have?
(1) a < 0
(2) n = 2k, where k is a positive integer
1) a<0austin wrote:If f(x) = x^n - a = 0, how many REAL roots does x have?
(1) a < 0
(2) n = 2k, where k is a positive integer
There's an issue with the wording here. When the question uses the word 'roots', what it means is 'solutions to the equation'. It makes no sense to talk about how many 'roots' x has in that case; they mean to ask how many roots 'x^n - a = 0' has, or as is sometimes said, how many roots f(x) has. If you simply talk about the 'roots' of a number or letter, it would be natural to take that to mean square roots, cube roots, and so on, which is not at all what the question is talking about. If the wording in the post above is that used in the source, then there are problems with that source.austin wrote:If f(x) = x^n - a = 0, how many REAL roots does x have?
(1) a < 0
(2) n = 2k, where k is a positive integer
ian that was a nice explanation related to roots..will keep it in mind.Ian Stewart wrote:There's an issue with the wording here. When the question uses the word 'roots', what it means is 'solutions to the equation'. It makes no sense to talk about how many 'roots' x has in that case; they mean to ask how many roots 'x^n - a = 0' has, or as is sometimes said, how many roots f(x) has. If you simply talk about the 'roots' of a number or letter, it would be natural to take that to mean square roots, cube roots, and so on, which is not at all what the question is talking about. If the wording in the post above is that used in the source, then there are problems with that source.austin wrote:If f(x) = x^n - a = 0, how many REAL roots does x have?
(1) a < 0
(2) n = 2k, where k is a positive integer
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