alokchaks wrote:
(1) The only perfect square in this range is 16. So √x can be +4 or -4. Not Sufficient.
(2) The possible values for √x are 3 and 4. Not sufficient.
Combining (1) and (2), we get √x = 4.
Ans C
Am I missing something?
Square root function can not give negative result.Any nonnegative real number has a
unique non-negative square root called
the principal square root and unless otherwise specified,
the square root is generally taken to mean
the principal square root.
When the GMAT provides the square root sign for an even root, such as
\sqrt{x} or
\sqrt[4]{x}, then the
only accepted answer is the positive root.
That is,
\sqrt{25}=5, NOT +5 or -5. In contrast, the equation
x^2=25 has TWO solutions, +5 and -5.
Even roots have only non-negative value on the GMAT.Odd roots will have the same sign as the base of the root. For example,
\sqrt[3]{125} =5 and
\sqrt[3]{-64} =-4.
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