Simple way to understand surds and rationalising the denominator?

Question

Whenever there's a root in the denominator I get lost. Can someone explain rationalising step by step with an easy example?

Dhanashree Adityaroy · Answer

The simple formula to remember here, is (a+b) x (a-b) =a2-b2.
So if the denominator has a square root, squaring the square root lands you on the same number! 
Eg  to rationalize 1/ √2 +3, multiply the  fraction by √2-3/√2-3.
Now the numerator will  become1(√2-3) = √2-3.
But the denominator, using the above formula, will become 2-9, which will be -7. 
The - sign will move to the numerator, and the final answer will be 3-√2/7.
I hope you have understood. 
God Bless You.

Simple way to understand surds and rationalising the denominator?

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