Attempt the question, check the explanation, and continue with similar questions to build confidence before exams.
ab^3 + 5a^2b + 10a^3
a^5 + 10a^4b + 5ab^2
5a^3b^2 + 15a^2b^3 + 10ab^4
15a^2b^3 + 20ab^4 + 5b^5
Continue with nearby questions to strengthen the same chapter concept while you still have the context fresh in mind.