Here, the formula for square of a binomial is used:

(A + B)^2 = (A + B)(A + B) = A^2 + 2AB + B^2

So, we plug: instead of A we put √x, and instead of B we put √2:

Also, do not forget that you can obtain an explanation for any step of the solution by clicking on it.

Please note that you cannot click on the very first expression, which is the original problem.