Answer
12 root 3
Answer is irrational (because it) can’t (and it’s decimal expansion) doesn’t (terminate or repeat)
You can see this by simply plugging the surd into the calculator 
Step-by-step explanation 
Sum of 2 root 3 and 5 root 12
Root 12 can be written as:
root 4 • root 3 
root 4 = 2 
= 2 • root 3
Multiply with the 5 from q
= 10 • root 3
Now the terms can be added
2 • root 3 + 10 • root 3 = 
12 • root 3