Question

when asked to factor the x^2 - 100, a student gives the answer (x -10) (x-10). what is wrong with this answer?

Answer 1

$x^2-100\\\\=x^2-10^2\\\\=(x+10)(x-10)\\\\\text{The difference of two squares formula is}~ a^2 -b^2 =(a+b)(a-b),\\\\\text{So, the student did not apply it properly}$