Question

Factorise :9-a^2+2ab-b^2

Answer 1

9-a^2+2ab-b^2

taking - sign common

9-(a2-2ab+b2)

now this is forming formula :-

(a-b)2=a2+b2-2ab

9 can be written as 3^2

(3)^2-(a-b)2

this is formed identity :-

a^2-b^2=(a+b)(a-b)

(3+a-b)(3-a+b)

Answer 2

9 - a² + 2ab - b²

= 9 - [a² - 2ab + b²]

= [3]² - [(a)² - 2(a)(b) + (b)²]

= [3]² - [a - b]²

= [(3)-(a-b)][(3)+(a-b)]

= (3-a+b)(3+a-b).