This function starts at [tex](0,3)[/tex], so we have [tex]f(0)=3[/tex].
Then, every time [tex]x[/tex] increments by 1, [tex]y[/tex] doubles. This is typical of exponential functions. In linear functions, every time [tex]x[/tex] increments by 1, [tex]y[/tex] increments by a fixed amount (the slope of the function).
So, this is an exponential function, and the equation is
[tex]f(x)=3\cdot 2^x[/tex]
