One such polynomial might be

Another with the same roots would be
Step b is wrong. The slope is the change in y over the change in x.
Step b should be (18- 8)/( 10-6)
= 10/4
= 5/2
The first dove terms are:3,9,12,15,18
The answer is 18. F(2) is saying that x is equal to 2. so where ever there is an x in the problem you should fill in 2 for. then all you have to do is type it into a graphing calculator and solve.
It’s c (plane) if your asking for two-dimensional set of points