Question

rationalise the following 1/7√2+5​

Answer 1

Answer⤵️

$\frac{1}{7 + 5\sqrt{2} }$

On Rationalization,

$= \frac{1}{7 + 5 \sqrt{2} } \times \: \frac{ 7 - 5\sqrt{2} }{7 - 5 \sqrt{2} }$

$= \frac{7 - 5 \sqrt{2} }{ {(7)}^{2} - (5 \sqrt{2})^{2} }$

$= \frac{7 - 5 \sqrt{2} }{49 - 50}$

$= \frac{7 - 5 \sqrt{2} }{ - 1}$

$= \frac{ - 1( -7 + 5 \sqrt{2} )}{ - 1}$

$= - 7 + 5 \sqrt{2}$

hope this helps!