If [math]\alpha[/math] is a root of [math]p(x)=x^n+a_{n-1}x^{n-1}+...+a_0[/math] where [math]a_i[/math] may be complex, how do I prove that [math]|\alpha |\leq \max \{1,|a_0|+|a_1|+...+|a_{n-1}|\}[/math]?