Question 54595
{{{f(x) = x^3-3x^2-x+3}}}
{{{f(x) = x^2(x-3)-(x-3)}}}
{{{f(x) = (x^2-1)(x-3)}}}
{{{f(x) = (x+1)(x-1)(x-3)}}}

Thus f(x) becomes zero when x = -1,1,3. Hence f(-1), f(1), f(3) are the zeros.