1. ## Factorisation

How would you factorise this example:

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

2. Hello, haku!

Factor: . $(x^2 - a^2)(x+b) - (x^2-b^2)(x+a)$

Keep factoring: . $(x-a)\underbrace{(x+a)(x+b)} - (x-b)\underbrace{(x+b)(x+a)}$
. . . . . . . . . . . . . . . . . . . . $\nwarrow$
. common factors . $\nearrow$

. . $= \;(x+a)(x+b)\,[(x-a) - (x-b)]$

. . $= \;(x+a)(x+b)(b-a)$

3. Thanks again for your help!