Hi!
Explanation: <u><em>This question is super super easy to me. This question is about how to use their order of operations the math problems. First you had to used PEMDAS stands for P-Parenthesis first, E-Exponents second, M-Multiply third, D-Divide fourth, A-Add fifth, and S-Subtract sixth. Then multiply and divide from left to right with 6*7=42. Then 27*9=243,42-243+64, and add or subtract from left to right with 42-243+64=-137 is the right answer. Hope this helps! And thank you for posting your question at here on Brainly. And have a great day. -Charlie</em></u>