Pls help me i do not know how to do this

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.

Justin has 750 more than eva and eva has 12 less than justin together they have a total of 63 how much money did

Ineed with math stuff it involves graphs