What is root two plus root two?

root 2 + root 2 = 2 root 2 or root 8

To find this answer this is what you do.

To add radicals the numbers under the radical must be the same (in this case they are both 2 so this step is already done)

Then even though you cannot see it there is a 1 in front of both of these radicals, so that means you have to add the 1's together.

1 root 2 + 1 root 2 = 2 root 2

Also the numbers under the radical do not change in this process.