The square root of a number [tex] y [/tex] is another number [tex] x [/tex] such that [tex] x^2 = y [/tex].
So, the square root of 25 is another number x such that [tex] x^2 = x \cdot x = 25 [/tex]
You can clearly see that the integer number 5 satisfies this request, so the square root of 25 belong to the integer numbers set, denoted as [tex] \mathbb{Z} [/tex]
