(i) 5x3 – 125x
5x3 – 125x
= 5x (x2 – 25)
= 5x(x2 – 52)
= 5x (x – 5) (x + 5)
(ii) 63a2 – 112b2
63a2 – 112b2
= 7 (9a2 – 16b2)
= 7 {(3a)2 – (4b)2}
= 1 (3a- 4b) (3a + 4b)
(iii) 9x2y2 – 16
9x2y2 – 16
= (3xy)2 – (4)2
= (3xy – 4) (3xy + 4)
(iv) (l + m)2 – (l – m)2
(l + m)2 – (l – m)2
= {(l + m) – (l – m)} {(l + m) + (l – m)}
= (l + m – l + m) (l + m + l – m)
= (2m) (2l)
= 4lm