Whats the property in this equation 6 + 3= 3 +6

Perform the indicated operation. 8/a - 6/a + 7/a

Of the ones listed here, the factor that had the greatest impact on the eventual destruction of native americans' ways of life was the development of the a) automobile. b) highway. c) railroad. d) steamboat.

Which of the following is the result of expanding the series