Question

factorise the following - (l+m)2 - (l-m)2​

Answer 1

Answer:

Using the identity: a² - b² = (a+b)(a-b)

(l+m)² - (l-m)²

= [(l+m)+(l-m)]×[(l+m)-(l-m)]

= [l+m+l-m]×[l+m-l+m]

= [2l]×[2m]

=4lm

Answer 2

Answer:

» (l + m)² - (l - m)²

= (l + m + l - m) (l + m - l + m)

= (2l) (2m)

= 4 (l m)