Question

if the value of my home has tripled since I bought it, that means its relative change in value is 300% true or false

Answer 1

I have to say it is true, since the value of the house was already 100, this is a simple math equation.  100 x 3= 300%

Answer 2

False.
Tripling a value means that it has increased by 200%. e.g. if something was originally $100 and it's value increased to $300, it would have tripled in price but only increased by 200%.
Hope this helps :)