Answer:
Let's try (x+5) first. According to the Remainder Theorem, if (x+5) is a factor of the polynomial, the remainder is zero.
when x+5=0, x=-5
use synthetic division:
-5 I 1 7 11 5
I -5 -10 -5
----------------------
1 2 1 0
the remainder is 0, so (x+5) is a factor:
the result is (x+5)(x²+2x+1)
factor again: (x+5)(x+1)(x+1) is the final answer.
