-53b² is the correct answer. First you had to remove parenthesis first, and it gave us, [tex]-26b^2-27b^2[/tex]. And then add similar elements, and it gave us the answer is [tex]-26b^2-27b^2=-53b^2[/tex], or -53b² is the right answer. Hope this helps! And thank you for posting your question at here on brainly, and have a great day. -Charlie