Question

$factorise \: it \\ {a}^{2} - {b}^{2} - a - b$

Answer 1

Hey there!
(a² -b² -a - b)

= (a² - b²) - ( a + b)

= ( a + b) (a - b) - ( a + b)

= ( a + b) ( a - b - 1 )

Hope helped!