1) If f(x) is a 4th degree polynomial, and has 3 real numbers as roots, the other root is?

2) What is (2+i \sqrt{2}), (2- i\sqrt{2} )?

3) What are the possible rational roots of f(x) = 5x⁴- 173x³-16x²-7x -15, according to the rational root theorem?"+-" means "plus or minus".