posted by student .
solve x^4-8x^3+64x-105=0 given that 2-i is one solution.
must be tired cause my steps are not calculating correctly
what you should do is show how far you got, if you want help.
another root is necessarily 2+i, so
(x^2-4x+5) divides x^4-8x^3+64x-105
x^4-8x^3+64x-105 = (x^2-4x+5)(x^2-4x-21)
Now it's a piece o' cake, no?