Respuesta :

altavistard
Justify "x2 = 25 is {±5}"

First, please write x^2, not x2.

x^2 = 25; solve for x.  Take the sqrt of both sides.  Must write "plus or minus " in front of the sqrt of 25:

x^2 = 25 becomes x = plus or minus 5, so x: {-5, 5}