Find the rationalisation factor
\[ 7 – 3\sqrt{5} \]
Solution:
\[ \text{Rationalisation factor of } (a – b\sqrt{c}) = (a + b\sqrt{c}) \]
\[ \therefore \text{Rationalisation factor of } (7 – 3\sqrt{5}) = 7 + 3\sqrt{5} \]
\[ 7 – 3\sqrt{5} \]
\[ \text{Rationalisation factor of } (a – b\sqrt{c}) = (a + b\sqrt{c}) \]
\[ \therefore \text{Rationalisation factor of } (7 – 3\sqrt{5}) = 7 + 3\sqrt{5} \]