Like in the title, I'm trying to prove
that if a^2 is algebraic over F, then a is algebraic over F.
my idea- by assumption, a^2 is a solution to the polynomial equation
b_n x^n + b_(n-1) x^(n-1) + ... + b_0 = 0 , b_n's are in F
if a^2 is in F, then we simply write a^2=a *a, and...