Question

1-2ab-(a^2+b^2) factorise

Answer 1

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

Explanation:

1 - 2ab - (a² +b²) = 1 - 2ab - a² - b²

= 1 - (2ab + a² + b²)

= 1 - (a + b)²

= 1² - (a +b)²

Identity: x² - y² = (x + y)(x - y)

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

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