What is the factorization of 49b2 - 81? (7b - 9) (7b - 9) (7b - 9) (7b 9) (7b2 - 9) (7b2 - 9) (7b2 - 9) (7b2 9)

The factorisation of 49b^2 - 81 is (7b - 9) (7b + 9). This is because 49 and 81 are the squares of 7 and 9 respectively, so these must be multiplied together. b^2 is b x b. Finally, it must be - 9 and + 9 to make - 81, because when the signs are the same the result is a positive number.