Each Point: 1 Mark
(i) (3x3−5x2−+8x+10)+(15x3−6x−23)+(9x2−4x+15)
=3x3−5x2+8x+10+15x3−6x−23+9x2−4x+15
Bringing like terms together, we get,
=3x3+15x3−5x2+9x2+8x−6x−4x+10−23+15
=18x3+4x2−2x+2
(ii) (3ab2−2b2+a2)+(5a2b−2ab2−3a2)+(8a2−5b2)
=3ab2−2b2+a2+5a2b−2ab2−3a2+8a2−5b2
Bringing like terms together, we get,
=3ab2−2ab2−2b2−5b2+a2−3a2+8a2+5a2b
=5a2b+ab2+6a2−7b2