Question

Factorise:
4a²+9b²+25c²-12ab-30bc+20ac​

Answer 1

Let's arrange these first

=> 4a² + 12ab + 9b² - (8a + 12b)

Here (2a + 3b) = 4a² + 12ab + 9b²

and

(8a + 12b) = 4(2a + 3b)

=> (2a + 3b)² - 4(2a + 3b)

=> (2a + 3b)(2a + 3b - 4)