a= 3+b, prove that a3 -b3 -9ab =27.

Where can I get similar questions for practise?

these type of questions are probably provided by meritnation.Just go to the chapter tests and do the mcqs of the chapter and u might find such questions in it and u might also find it in the question answers provided by meritnation or the model test paper.Ucan even use the test generator and also use assesment for knowing your weak areas.I m sure u will be able to find this solution.Also you can google for the similar types of questions