How would the expression x^2-7 be rewritten using difference of squares? someone me.

Every difference of squares problem can be factored as follows: a2 – b2 = (a + b)(a – b) or (a – b)(a + b). So, all you need to do to factor these types of problems is to determine what numbers squares will produce the desired results.
expression x^2-7 be rewritten using Difference of Squares
x^2 -(sqrt(7))^2

The correct answer for this question is this one: x^2 - sqrt(7) ^ 2

So, how were we able to get that answer.
The question asked us to have an equation of difference of squares.
That means, it is in the form of
a^2 - b^2

Since, the given equation has
x^2 - 7, so we need to have something that is equal to seven

7 = sqrt(7)^2