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Ahat [919]
3 years ago
7

Simplify the radical expression by rationalizing the denominator 4/√21

Mathematics
2 answers:
Tcecarenko [31]3 years ago
4 0

\frac{4}{\sqrt{21}} =\frac{4\sqrt{21}}{\sqrt{21}\sqrt{21}} =\frac{4\sqrt{21}}{21}

Lynna [10]3 years ago
3 0

I think

\dfrac{4}{\sqrt{21}}

is about as simple as this is going to get. For some reason teachers like the radicals in the numerator, so we multiply top and bottom by \sqrt{21} and get

\dfrac{4}{\sqrt{21}} \times \dfrac{\sqrt{21}}{\sqrt{21}} = \dfrac{4\sqrt{21}}{21}

Answer: \dfrac{4\sqrt{21}}{21}

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