Question

how to rationalise a denominator?

Answer 1

step 1 : multiply numerator and denominator by a radical that will get rid of the radical in the denominator ..

step 2 : make sure all radicals a simplified .....

step 3 : simplify the fraction if needed ...

Answer 2

To rationalise denominators just multiply the numerator and denominator with the number which is same but of opposite sign of denominator.

Example:-
(a+b)/(c-d)

Rationalising denominator:-
(a+b)/(c-d) × (c+d) / (c+d)

We can also write it as:-
(a+b)(c+d)/(c-d)(c+d)

Hope it helps.