(i) 3mn, -5mn, 8mn, -4mn
3mn + 8nm – 5mn – 4mn
(re-arranging the terms)
= 11mn – 9mn = 2mn
(ii) t – 8tz, 3tz – z, z – t
= t - t, -8tz + 3tz - z - z
(re-arranging the terms)
= -8tz + 3tz = -5tz
(iii) -7mn + 5, 12mn + 2, 9mn – 8, – 2mn – 3
-7mn + 12 mn + 9mn – 2mn + 5 + 2 – 8 – 3
(re-arranging the terms)
= -7mn – 2mn + 12mn + 9mn + 7 – 11
= -9mn + 21 mn -4
= 12mn – 4
iv) a + b -3, b – a +3, a – b + 3
= a - a + a + b + b - b - 3 + 3 + 3
(re-arranging the terms)
= (2a – a + 2b – b + 6 – 3)
= a + b + 3
(v) 14x + 10y – 12xy – 13, 18 – 7x – 10y + 8xy, 4xy
(re-arranging the terms)
= 17x + 51
(vi) 5m – 7n, 3n – 4m + 2, 2m – 3mn – 5
(re-arranging the terms)
= 5m – 4m + 2m – 7n + 3n – 3mn + 2 – 5
= 7m – 4m – 7n + 3n – 3mn – 3
= 13m – 4n – 3mn – 3
(vii) 4x2y, – 3xy2, 5y2, 5x2y
(Re-arranging the terms)
4x2y + 5x2y – 3xy2 – 5xy2
= 9x2y – 8xy2
(viii) 3p2q2 – 4pq + 5, 10p2q2, 15 + 9pq + 7p2q2
3p2q2 – 10p2q2 + 7p2q2 – 4pq + 9pq + 5+ 15
(Re-arranging the terms)
= 3p2q2 + 7p2q2 – 10p2q2 – 4pq + 9pq + 5 + 15
= 10p2q2 - 10p2q2 + 5pq + 20
= 5pq + 20
(ix) ab – 4a, 4b – ab, 4a – 4b
= ab - ab - 4a + 4a + 4b - 4b
(Re-arranging the terms)
(All terms are cancelling)
= 0
(x) x2 – y2 – 1, y2 – 1 – x2, 1 – x2 – y2
(Re arranging the terms )
= x2 - x2 - x2 - y2 + y2 - y2 - 1 - 1 + 1
= -x2 – y2 – 1