8. Since A F is perpendicular to J K, you know angles J A F and K A F are congruent (both are right angles). Since A F bisects J K, you know the lengths of J A and K A are the same. Side A F is incident to both triangles, and of course the lengths A F = A F. So we have two side-angle-side triangles, and by the SAS postulate we have triangles J F K and K F A congruent to one another.
9. Yes. The corresponding sides in both triangles have the same lengths. (S K to K F; S J to F J; J K to itself) The claim then follows from the SSS postulate.
In any polynomial when you have an imaginary root, there is always another imaginary root that is the conjugate of the first one: 1st root: 4 + 17i 2nd root: 4 - 17i (the conjugate of the 1st one)