I need someone to explain the steps in finding all zeroes of an equation

Question

x^4-6x^2-7x-6=0

Answer 1

you know the rational roots, if any, are among ±1 ±2 ±3 ±6

so, try some and fond that -2 and 3 are roots.

dividing those out you find you have

(x+2)(x-3)(x^2 + x + 1)

find the other two roots using the quadratic formula

Answer 2

Steve I do not understand how to use the quadratic formula to find the other roots would you please explain?

Answer 3

This does not help me out.