Hi,
Answer: -11.7
My work: This problem can be easily achieved by taking the number -2.7 and subtracting it with 5.9. (-2.7 - 5.9) Your next step would be to taking the number -8.6 and subtracting it with 3.7. Which brings it to your answer -11.7.
My Numerical work:
1. -2.1+(-5.9)+(-3.7)
2. -2.1 - 5.9 - 3.7 = -11.7
I Hoped I Helped!