Using the Derivative of F(x) Given Below, Determine the Intervals $$f ^ { \prime } ( x ) = ( 8 - x ) ( 9 - x )$$

question 136

Multiple Choice

Using the derivative of f(x) given below, determine the intervals on which f(x) is increasing or decreasing.
- $$f ^ { \prime } ( x ) = ( 8 - x ) ( 9 - x )$$

• A) Decreasing on \(( - \infty , 8 )\); increasing on \(( 9 , \infty )\)
• B) Decreasing on \(( 8,9 )\); increasing on \(( - \infty , 8 ) \cup ( 9 , \infty )\)
• C) Decreasing on \(( - \infty , - 8 ) \cup ( - 9 , \infty )\); increasing on \(( - 8 , - 9 )\)
• D) Decreasing on \(( - \infty , 8 ) \cup ( 9 , \infty )\); increasing on \(( 8,9 )\)

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