Question

answer is urgent pls​

Answer 1

a² + 4b² - 4ab - 9c²

= {a² - 4ab + 4b²} - (3c)²

= {(a)² + (2b)² - 2(a)(2b)} - (3c)²

∵ x² + y² - 2xy = (x - y)²,

= {(a - 2b)²} - (3c)²

= (a - 2b)² - (3c)²

∵ x² - y² = (x + y)·(x - y)

= [(a - 2b) + (3c)]·[(a - 2b) - (3c)]

= (a - 2b + 3c)(a - 2b - 3c)