12+root of 35 divided by 2 + 12-2 root of 35 divided by 2

So : ?

First, you want to bring everything together on the top of the fraction. 
12=24/2 so you can have 

Add like terms -- 12 +24 = 36       

Now we are at  Which is the lowest possible simplified version while remaining at exact value. 

Feel free to check my math! I kinda did this off the top of my head. 

The answer is why would a teacher ask that