We first find the zeros of the function , the zeros of the function are those at which points the graph of the function crosses or touches the x axis
here we can see in the graph that graph crosses the x axis at two points , 1 and 7
So the zeros of the function are
x=1 and x=7
It means the factor are
(x-1) and (x-7)
So the factorization is given by
(x-1)(x-7)