Hi! Ive been trying to do these problems for a while and Im stumped. I finished 13 problems and fully understand them , but I don't know how to do these problems. It would be nice if you could write each step out or the answer at the very least. Or hints or tips, like which theorem or something to use. Shortcuts.

3. Find the quadratic equation. Use only integral coefficients

-2 - (3/2)i, -1, 5

What do you do in this problem O_o

4) Solve x4 + 2x3 +14x2 + 8x + 40 = 0 , given that 2i is a root.

I think there are shortcuts for this one. But I dont know them

Is there any shortcuts?

5. Can anyone explain the Descartes Rule of Signs?