Question

Factorise 100a^2-81b^2

Answer 1

In this question, you'll apply algebraic identity 3 which is:

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

As you can see, 100a^2 - 81b^2 is in the form a^2 - b^2. Thus, we can use the 3rd to identity to factorize:

100a^2 - 81b^2

(10a)^2 - (9b)^2

(10a+9b)(10a-9b)

Final answer: (10a+9b)(10a-9b)

I hope this helps!! :)