Add: 3+2y−5y2+6y3,−8+3y+7y3 and 5−6y−8y3+y2.
3+2y−5y2+6y3 −8+3y +7y3 5−6y+y2 −8y3–––––––––––––––––––––– −y −4y2+5y3
Adding 3+2y−5y2+6y3,−8+3y+7y3 and 5−6y−8y3+y2, we get