Surds

[iAdam]

Right I need help with surds, I just don't get them sometimes, this is one of these times and I have homework on them. -.-

Right can anyone answer these quesiton to help me;

V= Square root

5V2+V2
9V5-V5
V20-V5
V27-V3
V20/V5

Rationalise the denominators of these fractions:
A. 2 / V3


I really don't get it and need help urgently.

[Jesus-Egg]

For the first one, just think of it like doing 5x + x, except x=√2. So 5√2 + √2 = 6√2. The rest are the same sort of thing. In the 3rd one, note that 20 = 4*5, and of course √4 = 2, so √20 = √(4*5) = √4√5 = 2√5. In the last one, rationalising the denominator just means get red of the square root from the bottom of the fraction. All you have to do is multiply top and bottom by √3. Hope this helped.

[iAdam]

That really did help, I'll work through them now thanks