Question

write in the simplest form 

Answer 1

You will FOIL this out to simplify. First outers, inners last. 2*1 = 2; 2*2sqrt7 = 4sqrt7; -sqrt7*1=-sqrt7; -sqrt7*2sqrt7 = 2sqrt49. This is what all that looks like:
. Combining like terms we have
. The sqrt 49 is equal to 7, so we can continue simplifying:
which equals
. Finally,
. Or, putting the positive term first, it would also be correct to write