**since this is already factored out**
**f(x)=x^2(x+3)(x^2-1)?**

show work please

presume you mean find the values of x so that

\(\displaystyle x^2(x+3)(x^2-1) = 0\)

since this is already factored out. then setting any one of the factors to zero will work so..

if \(\displaystyle x^2 = 0\) then \(\displaystyle x = 0\)

if \(\displaystyle x+3=0\) then \(\displaystyle x=-3\)

if \(\displaystyle x^2-1 = 0\) then\(\displaystyle x= 1 \)or \(\displaystyle x= -1\)