Find all roots of P(x)= X^4 - 7/2 X^3 + 6x^2 -28x -16

Answer 1

Quartics are g=hard to solve, so look for rational roots, if any, where the numerator must be among

±1 ±2 ±4 ±8 ±16

A little synthetic division yields

P(x) = (x-4)(x + 1/2)(x^2+8)

I guess you can find the roots from there...