SAT Mathematics Practice Test 3

If $\mathit{x}-\mathit{b}$ is factor of $\mathit{f}\left(\mathit{x}\right)$.then $\mathit{f}\left(\mathit{b}\right)$ must equal 0.
Based on the table,$\mathit{f}\left(4\right)=0$,Therefore,$\mathit{x}-4$ must be a factor of $\mathit{f}\left(\mathit{x}\right)$
Choice A is incorrect because $\mathit{f}\left(2\right)\ne 0$;
choice B is incorrect because no information is given about the value of $\mathit{f}\left(3\right),$ so $\mathit{x}-3$ may or may not be a factor of $\mathit{f}\left(\mathit{x}\right);$
and choice D is incorrect because $\mathit{f}\left(5\right)\ne 0$.