For this case we have the following expression: -5a ^ 2b + 10ab ^ 2 - 20b + 25a ^ 3b We observe that the term 5b is repeated throughout the expression, therefore it is a common factor. So, factoring we have: 5b (-a ^ 2 + 2ab - 4 + 5a ^ 3) Then, rewriting we have: 5b (a ^ 2 (5a-1) + 2ab-4) Answer: The factored expression is given by: 5b (a ^ 2 (5a-1) + 2ab-4)
