Answer :

mariamikayla
[tex]2a+3b+a+5b\to\boxed{3a+8b}[/tex]
SoapMcTavish
first, you group the numbers which have the same radicals: 2a+a+3b+5b
Then, you add the same radical numbers: 3a+8b
you keep adding till you can't add numbers anymore
P.S. a = 1a
P.S. you can't add numbers with different radicals 
Hope this helps :D