Answer: 130875 automobiles
Explanation:
To estimate the total number of automobiles owned in 2005, let's first find the number of years
2005 - 1990 = 15 years
Given that the Commercially owned automobiles in the United States can be modeled by the function
A(x) = 1.4x – 130.6x² + 1831.3x + 128,141, where x is the number of years after 1990
and A(x) is the number of automobiles in thousands.
Substitute 15 for x in the function
A(x) = 1.4(15) – 130.6(15)² + 1831.3(15) + 128,141
A(x) = 21 - 29385 + 27469.5 + 128141
A(x) = 126246.5 automobiles
The number of privately-owned automobiles in the United States can be modeled by the function
P(x) = -x + 24.9x² – 177.9x + 1709.5, where x is the number of years after 1990
Substitute 15 for x in the function
P(x) = -(15) + 24.9(15)² – 177.9(15) + 1709.5
P(x) = -15 + 5602.5 - 2668.5 + 1709.5
P(x) = 4628.5 automobiles
The total automobile = A(x) + P(x)
Substitutes for A(x) and P(x)
The total automobile = 126246.5 + 4628.5
= 130875
Therefore, the total number of automobiles owned in 2005 is 130875 automobiles