Rationalise the denominator of 25/sqrt(5)

In maths when we are asked to re express something we really only have 2 tricks. Multiply by 1, or add Zero. The hard part is finding how to express 1 or zero to suit the problem. For this one we should multiply by sqrt(5)/sqrt(5) = 1. We multiply the top and bottoms individually and unisng the definition of a square root we have 25/sqrt(5) * sqrt(5)/sqrt(5) = 25sqrt(5)/5 = 5sqrt(5)