$$x^5 - 5x^4 +6x^3 -30x^2 +8x - 40 = 0$$
So far I have... $$r/s: +- 1, +- 40, +- 2, +- 20, +- 4, +- 10, +-5, +- 8$$ Only $+ 5$ works. Then I have $$(x + 5)( ) = x^5 - 5x^4 +6x^3 -30x^2 +8x - 40$$ Then you have to use long devision between $x + 5$ and $ x^5 - 5x^4 +6x^3 -30x^2 +8x - 40$ That's where I get lost. Help?!