Question

answer fast
factorise ​

Answer 1

ur answer is (3x-y)(3x+y)

this is because on taking

a square - b square formula

Answer 2

$9 {x}^{2} {y}^{2} - 16 \\ = (3xy) ^{2} - {4}^{2} \\ = (3xy + 4)(3xy - 4)$

$( {x}^{2} - 2xy + {y}^{2} ) - {z}^{2} \\ = (x - y)^{2} - {z}^{2} \\ = ( x - y + z)(x - y - z)$

$(l + m)^{2} - (l - m)^{2} \\ = (l + m + l - m)(l + m - l + m) \\ = (2l)(2m) \\ = 4lm$

The Main Identity Used here is

${x}^{2} - {y}^{2} = (x + y)(x - y)$