Here are my ideas for the questions...
In question 1, expanding we get
So we have
Then from 
And from 
For question 2,
If you factor you get
Then by the factor theorem...
You should be able to solve either for k...
Haha! My calculator got k = 7 after a very... long time. And I had to resort to iteration. Surely there is a more efficient way to do this.