Answer
$[(x-1)+1]^{5}=x^{5}$
Work Step by Step
We need to factor:
$(x-1)^{5}+5(x-1)^{4}+10(x-1)^{3}+10(x-1)^{2}+5(x-1)+1$
We notice that this corresponds to an expanded binomial with a power of $5$ and terms $x-1$ and $1$:
$[(x-1)+1]^{5}=x^{5}$