Factorise. (i) `4p^2 - 9q^2`
(ii) `63a^2 - 112b^2`
(iii) `49x^2 - 36`
(iv) `16 x^5 - 144x^3`
(v) `(l + m)^2 - (l--m)^2`
(vi) `9x^2y^2 - 16`
(vii) `(x^2 - 2xy + y^2) - z^2`
(viii) `25a^2 - 4b^2 + 28bc - 49c^2`

Explanation

(i) `4p^2 - 9q^2`

`(2p)^2 - (3q)^2`

`(2p- 3q)(2p+3q)`

(ii) `63a^2 - 112b^2`

`(sqrt63 a)^2 - (sqrt112 b)^2`

`= (sqrt63 a - sqrt112b)(sqrt63 a + sqrt 112 b)`

(iii) ` 49x^2 - 36`

`(7x)^2 - (6)^2`

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