Square Root
\( x^2 = 81 \) has two solutions, -9 and 9.
But does \( \sqrt{81} \) have one solution or two?
Is it correct to say that \( \sqrt{81} \) = +9 and -9?
Or should we be saying that \( \sqrt{81} \) is an expression and that \( 9\), \(\frac{18}{2} \), \(27^{2/3} \), and \(1+6+2\), are equivalent expressions?
It is really alarming how often I see materials written by math teachers claiming that for example sqrt(81) is both 9 and -9.
- Kate Nowak (@k8nowak) April 22, 2015
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