Question

Factorise: 49a² - 4b² + 20bc - 25c²​

Answer 1

Answer:

49a^2-4b^2+20bc-25c^2

=(7a)^2-(4b^2-20bc+25c^2)

=(7a)^2-{(2b)^2-2.2b.5c+(5c)^2}

=(7a)^2-(2b-5c)^2

={7a+(2b-5c)}{7a-(2b-5c)}

=(7a+2b-5c)(7a-2b+5c)

Answer 2

Answer:

(7a+2b-5c)(7a-2b+5c)