yes, if it is in brackets and the equation is doubled. (These are the words of my grade 12 teacher)
x2 =1 or -1, this one is the most basic of them all
Yes, it often does. If you use the discrimnant, and the answer is <0, there is no answer, if it equals 0, there is one answer, and if it is >0 there are 2 answers
Definitely. The equation [ x2 = 9 ] has two solutions. x = +2x = -2