What does proportional and no proportional mean?

On a piece of paper graph f(x)=5•(0.4)^x

What is the result of adding the system of equations? 2x+y=4 3x-y=6

Will give let f(x)=2x and g(x)=[tex]2^{x}[/tex] graph the functions on the same coordinate plane. what are the solutions to the equation f(x)=g(x) ? enter your answers in the boxes x=[? ] or x=[? ]