How do I do questions 15 and 16? Thank you

Electricity Consumption The table below gives the retail sale of electricity (in billions of kilowatt-hours) for the residential and commercial sectors of the United States. Residential {billions of kilowatt-hours) 1,192 1,276 1,400 1,420 1,402 1,390 Let :1: represent time (in years) with a: : 0 corresponding to 200C}, and let y represent the corresponding residential sales. Find the quadratic regression equation for the data y=R($)=a$2+b$lc 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. Use this quadratic model to answer the questions below. Question 15 4 pts Use the regression model found above to predict the residential retail sale of electricity in 2027. Round to the nearest billion of kilowatt-hours. NOTE: You may get the wrong answer if you do not use the quadratic model with coefcients rounded as described above. billion of kilowatt-hours Question 15 4 pts Use the regression model found above to predict the residential retail sale of electricity in 2027. 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 Question 16 4 pts Use the regression model found above to predict the instantaneous rate of change in residential retail sale of electricity in 2030. 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