Question

factorise using identity x-y-x2+y2​

Answer 1

$x - y - {x}^{2} + {y}^{2} \\ = x - y - ( {x}^{2} - {y}^{2} ) \\ = (x - y) - {((x - y) \times (x + y))} \\ = (x - y){(1 - (x + y))} \\ = (x - y)(1 - x - y)$

Identity used:

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