Quadratic function and exponential function question!

hi, it's me again. Thanks so much for the help last time. :)

i have this table of values:

x | y

1 | 20

3 | 320

i have to make a linear, quadratic, and exponential function from these values.

i used y-y1=m(x-x1) for the linear and came up with f(x)= 150x-130

am i supposed to use the quadratic formula to find the quadratic function? i tried but I ended up being unable to find an answer (undefined?). can someone please walk me through this? maybe I just need the values for a, b, and c.

as for the exponential function, i am completely clueless... (Doh)

as always, i am not allowed to use a calculator for these problems, so i hope someone can guide me through the steps.(Nod)