The quadratic equation is in factored form, which is f(x) = (x - a)(x - b), where a and b are the x-values for the x-intercepts.
The x-values for the x-intercepts are 4 and -2. We know that the y-value at any x-intercept must be 0 (otherwise it isn't an x-intercept).
Thus, either the points (4,0) or (-2,0) must be your answer (the question is only asking for one x-intercept).