Need help ASAP, Pre-calc, What are all real possible solutions of the equation (IMAGE attached)

Given
[tex]h(x)=(x+3)(x^2+1)(x-4)[/tex]Answer
The possible real solutions are -3 and 4 as x+3 is zero at x=-3 and x-4 =0 at x=4 middle term can not be zero for any real value of x.