Question

Factorise using identity :
a) 25-4x2-12xy-9y2

Answer 1

Answer:

(5-2x+3y)(5-2x-3y)

Step-by-step explanation:

25-4x^2-12xy+9y^2

= 25-(2x-3y)^2                       (Since (a-b)^2 = a^2 + b^2 - 2ab)

= (5)^2 - (2x-3y)^2

= (5-(2x-3y))(5+(2x-3y))         (Since a^2-b^2 = (a-b)(a+b)

= (5-2x+3y)(5+2x-3y)