Agriculture—Fuel Ethanol Production: One of the renewable fuels that have been promoted ov...

Agriculture—Fuel Ethanol Production: One of the renewable fuels that have been promoted over the past few decades is corn-based ethanol. “Without the renewable-fuels standard, etha- nol really wouldn’t be a viable business,” said Bill Day of ethanol producer Valero. (Source: The National Journal.) The annual amount of corn-based ethanol produced from 1980 to 2010 can be modeled by

where x represents the number of years since 1980, and f(x) represents the amount of corn-based ethanol produced in millions of barrels. (Source: U.S. Energy Information Administration.)

(a) Determine the equation of the vertical asymptote for the graph of f, and write it in the form x = a.

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(b) Use the value of a from part (a) to determine , and interpret the result.