Question

rationalise the dinominator of 1 upon 4+√5
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Answer 1

Step-by-step explanation:

$\frac{1}{4 + \sqrt{5} } \times \frac{4 - \sqrt{5} }{4 - \sqrt{5} } \\ = \frac{4 - \sqrt{5} }{ {4}^{2} - ( \sqrt{5} ) ^{2} } \\ = \frac{4 - \sqrt{5} }{ 16 - 5} \\ = \frac{4 - \sqrt{5} }{11}$