Subtract:
(i) -5y2 – from y2
(ii) 6xyfrom -12xy
(iii) (a - b) from (a + b)
(iv) a(b - 5) from b(5 - a)
(v) -m2 + 5mn from 4m2 – 3mn + 8
(vi) -x2 + 10x – 5 from 5x -10 x2
(vii) 5a2 - 7ab + 5b2 from 3ab – 2a2 -2b2
(viii) 4pq - 5q2 - 3p2 from 5p2 + 3q2 - pq
(i) y2 - (-5y2)
= y2 + 5y2
= 6y2
(ii) -12xy - 6xy = -18xy
(iii) (a + b) - (a - b)
= a + b - a + b
= a - a + b + b
=2b
(iv) b(5 - a) - a(b - 5)
= 5b - ab - ab + 5a
=5a + 5b - ab - ab
= 5a + 5b - 2ab
(v) 4m2 - 3mn + 8 - (-m2 + 5 )
= 4m2 - 3mn + 8 + m2 - 5
= 4m2 + m2 - 3mn + 8 - 5
= 5m2 - 3mn + 3
(vi) 5x - 10 - (-x2 + 10x - 5 )
= 5x - 10 + x2 - 10x + 5
= x2 + 5x - 10x - 10 + 5
= x2 - 5x - 5
(vii) 3ab - 2a2 - 2b2 - (5a2 - 7ab + 5b2)
= 3ab - 2a2 - 2b2 - 5a2 + 7ab - 5b2
= -2a2 - 5a2 + 3ab + 7ab - 2b2 - 5b2
= -7a2 + 10ab - 7b2
(viii) 5p2 + 3q2 - pq - (4pq - 5q2 - 3p2)
= 5p2 + 3q2 - pq - 4pq + 5q2 + 3p2
= 5p2 + 3p2 + 3q2 + 5q2 - pq - 4pq
= 8p2 + 8q2 - 5pq