Answer
(3.5, -5.5)
Work Step by Step
To solve a system with a calculator you need transform the equations into this form: ax+by=c
$ y=3.1x-16.35<=>-3.1x+y=16.35$
$ y=- 9.7x+28.45<=> 9.7x+y=28.45$
After that you can insert these into the calculator and it will solve the system.