Question

Sales of SUVs​ (sport utility​ vehicles) in the United States ​(in millions) for the years​ 1990-1999 can be modeled by the quadratic equation shown below.

y = 0.016x^2 + 0.124x + 0.787
Here x=0 represents​ 1990, x=1 represents​ 1991, and so on. Use the model to approximate sales in 1998.

Sales in 1998 were approximately __ million SUVs.

Answer 1

If x = 0 is 1990, x = 1 is 1991, then 1998 is represented by x = 8. Substitute this value of x into the quadratic equation to find y:
y = 0.016*(8^2) + 0.124*8 + 0.787 = 1.024 + 0.992 + 0.787 = 2.803
Therefore, there were approximately 2.803 million SUVs sold in 1998.