Let's explore some maths and different options here...
#1.rarr#The most obvious and most boring method is to pick up a calculator. press some keys and you get the answer.
#2.rarr#There is a square root to be calculated in each term. Many students do not really understand what a square root does. In this case even if you use the incorrect method of just dividing by 2, you will still get the right answer.
#2color(red)(sqrt4) + 2color(red)(sqrt4) = 2xxcolor(red)(2)+2xxcolor(red)(2) = 4+4 = 8#
#3.rarr# Did you notice that the two terms are like terms?
We could therefore add them first, and then find the square root
#color(blue)(2)sqrt4 +color(blue)(2)sqrt4 = color(blue)(4)sqrt4 = 4xx2 = 8#
My method of choice would be option 3, because in an algebraic expression such as
#3sqrta + 5sqrta# you can still add the like terms to get #8sqrta#
Maths is less about the answer and more about the understanding and the method and the process.
Sometimes the unusual routes are more enjoyable.
