With 3 the leading coefficient and 1 the constant, either 1/3 or -1/3 is likely to be a root of the poly in #11. Use synth. division to check this out:
______________
(-1/3) / 3 3 1 1
-1 -2/3 -1/9
-------------------------
3 2 1/3 8/9 Since the remainder is not zero, -1/3 is unfortunately not a root and 3x+1 is not a factor.
A better approach may be factoring by grouping. We see that 3x^3 + 3x^2 factors into 3x^2(x+1). Also, x+1 factors into 1(x+1). The common factor here is x+1. So the given poly becomes (3x^2 + 1)(x+1) (these are your
factors).