Question

Factorise it...........

Answer 1

Answer:

0.81b3-b

b(0.81b2-1)

Answer 2

Answer:

b(0.9+1)(0.9-1)

Step-by-step explanation:

0.81b^3-b

=b(0.81b^2-1)

=b{(0.9b)^2-1^2}

=b{(0.9b+1)(0.9b-1)}                                    {because a^2-b^2=(a+b)(a-b)}

=b(0.9b+1)(0.9-1)

I hope this helps........