Use the rational root theorem
a0=16, an=1
The dividers of a0: 1,2,4,8,16 The dividers of an:1
Therefore check the following rational numbers: +- 1,2,4,8,16/1
4/1 is a root of the expression, so factor out x-4,
compute (x^4+13x^3-64x^2-20x+16)/(x-4) to get the rest of the equation:
x^3+17x^2+4x-4
=(x-4)(x^3+17x^2+4x-4)/x-4
which will leave you with answer B
x^3+17x^2+4x-4
