Question

factorise : a2 (b – c) + b (c – b)​

Answer 1

a²(b-c) + b(c-b) (notice that c and b are common but they are different signs, so in order to make them the same, we'll change the sign of b outside the brackets)

a²(b-c) - b(-c+b) (since I changed the sign outside I change it inside too and now both are common)

a²(b-c) -b(b-c) (this can be written like this)

(a²-b)(b-c)

hope it helps

have a great day

(if you want the step by step explanation please post the question again, I'll answer with full explanation)