Question

find all roots of the polynomial equation. x^5+3x^4-2x^3-14x^2-15x-5=0.

Answer 1

Trying x = ± 1, ± 5
I get a zero when x = -1
by synthetic division:
(x+1)(x^4 + 2x^3 - 4x^2 - 10x - 5) = 0
well, what do you know, x = -1 works again, so
(x+1)(x+1)(x^3 + x^2 - 5x - 5) = 0
grouping the last part
(x+1)(x+1)( x^2(x+1) - 5(x+1) ) = 0
(x+1)(x+1)(x+1)(x^2 - 5) = 0

(x+1)^3 (x^2 - 5) = 0
x = -1 or x = ± √5

Answer 2

that's exactly what I got but it keeps saying it is wrong.