For some reason this is throwing me off.

Given :http://www.reynoldszoo.com/1/given.jpg

Already found one zero at -1. Book has 3 zeros but given that it's degree 4 shouldn't it have 4 zeros?

http://www.reynoldszoo.com/1/ans.jpg

And how do I get the complex zeros?

Sorry for having to use pics but i cant figure out the way you all do it yet :)