we have the equation

this is the equation of a vertical parabola open downward
that means
the vertex is a maximum
using a graphing tool
see the attached figure
Part a
the vertex is the point (4.667, 2.06)
interpret the vertex
that means
For the year -----> 2015+4.665=2019.67=2020
the production is 2.06 billion of barrels of crude oil
Part b
What does the model predict the crude oil production will be in 2038?
For x=2038-2015=23 years
substitute the value of x in the given equation

y=1.052 billion of barrels of crude oil
Part c
Graph the function for the years 2015 to 2035
2015 ------> is For x=0
2035 ----> is For x=2035-2015=20
see the attached figure