Solve for k: (Two different types of problems)

Hi all, thanks for taking time out of your day to have a look at my problems. I'm studying and need some help solving these two problems.

I need to solve for k:

Here are the problems:

1) One root of 6x^2 - 3x +k = 0 is (1 - i√23)/4

2) kx^2 - 3x + 4 = 0 one root is twice the other.

I'm not really sure how to do these problems and am really greatful for your help! Btw, the "√" sign in the first problem is a square root sign (just in case someone got confused).

Thanks! (Happy)