Last one:

(3):
(i) Show that \mathbb{F}(x)/(x^2 -1) \cong \mathbb{F} \times \mathbb{F} when \mathbb{F} is any field in which  1 + 1 \neq 0 .
(ii) Show that \mathbb{R}(x)/(x^2 + a) \cong \mathbb{C} if a > 0, or \mathbb{R} \times \mathbb{R} if a < 0.

any suggestions on these please? thnx