Question 306050
2sqrt(2)-15sqrt(3)+20sqrt(6)=25.837
We start with:
13sqrt3 + 4sqrt150 - 7sqrt48 + 2 sqrt2
We can reduce 4sqrt(150) and -7sqrt(48)
4sqrt(150)=4sqrt(25*6)=20sqrt(6)
-7sqrt(48)=-7sqrt(16*3)=-7*(4)sqrt(3)
13sqrt(3)-28sqrt(3)=-15sqrt(3)

We end up with 
2sqrt(2)-15sqrt(3)+20sqrt(6)=25.837
I have no idea what you did.