The table below gives the retail sale of electricity (in billions of kilowatt-hours) for the residential and commercial sectors of the United States.

Year	Residential (billions of kilowatt-hours)
2000	1,192
2003	1,276
2006	1,400
2009	1,420
2012	1,402
2015	1,390

Let x represent time (in years) with x=0 corresponding to 2000, and let y represent the corresponding residential sales. Find the quadratic regression equation for the data

y=R(x)=ax2+bx+c

with a rounded to the nearest hundredth (2 decimal places), b rounded to the nearest tenth (1 decimal place), and c rounded to the nearest integer. (See the Regression page in the Getting Started module for ways of computing a regression model.)

Use this quadratic model to answer the questions below.

Use this quadratic model above to answer this question.

Predict the residential retail sale of electricity in 2025. Round to the nearest billion of kilowatt-hours. NOTE: You may get the wrong answer if you do not use the quadratic model with coefficients rounded as described above.

billion of kilowatt-hours

Use this quadratic model above to answer this question.

Predict the instantaneous rate of change in residential retail sale of electricity in 2023. Round to the nearest billion of kilowatt-hours. NOTE: You may get the wrong answer if you do not use the quadratic model with coefficients rounded as described above.

billion of kilowatt-hours per year

NOTE: Your answer might be negative.