The degree of a polynomial is the greatest exponent. In this case, the degree is 8.
The polynomial is a trinomial because it has 3 terms.
This is an exponential growth problem. Exponential growth can be expressed mathematically in the following way:

.
Parameter a presents initial amount.
Parameter r is percentage increase.
Parameter t is time.
An equation that would describe given problem is:

t is the time in years.
I attached the graph of this function.
Your answer can be anything in the form y = mx+8 where you replace m with any real number.
You start with y = mx+b, and then replace the b with the y intercept 8.
The y intercept is where the polynomial crosses the y axis.
The value of m does not matter. So you could have y = 2x+8 or y = 3x+8 for instance. Replace m with whatever your favorite number is.
-3x+1 just do the opposite
Should be 1/4 to my knowledge.