Find all zeroes of a polynomial x4 + x3 – 34x2 – 4x + 120, if two zeroes are 2 and -2.

Answer 1

The zeroes can be written as

(x-2)(x+2) = x²-4

Divide the function by x²-4 using Polynomial Long Division

You should get x²+x-30

Then factor that into (x+6)(x-5)

Set each equal to zero so the other zeroes are -6 and 5