Question

Anyone know synthetic division?

Answer 1

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