Question

rationalise the denominator of

$\frac{1}{7 + 3 \sqrt{2} }$
​

Answer 1

answer

$\frac{1}{7 + 3 \sqrt{2} } \\ = \frac{1}{7 + 3 \sqrt{2} } \times \frac{7 - 3 \sqrt{2} }{7 - 3 \sqrt{2} } \\ = \frac{7 - 3 \sqrt{2} }{ {7}^{2} - {(3 \sqrt{2} )}^{2} } \\ = \frac{7 - 3 \sqrt{2} }{49 - 18} \\ = \frac{7 - 3 \sqrt{2} }{31}$

ans = 7-3√2/31