For 3+(8‾√+11)=(3+8‾√)+11, the property is associative property. This means that if you are adding three real numbers, it does not matter if you add the first two first or the last two first. For example, 4+(5+6)= (4+5)+6. For 3+8+11=3+8+11, the property is the reflexive property, which shows how something relates to itself. For example, 5=5 and x=x.
