$\"\"$

The function is $\"f$

$\"fraction$ (Apply the derivative)

$\"f$ (Apply the sum rule)

$\"f$ (The power rule: $\"fraction$ )

$\"f$ (Simplify)

$\"\"$

To find the critical number then f\\'(x) = 0

$\"f$

$\"2$

$\"2$ (Subtract 6 from each side)

$\"x$ (Divide each side by 2)

$\"\"$

Because there are no points for which f\\' does not exist, you can conclude that $\"x$ the only critical number. The table summarizes the testing of the two intervals determined by these one critical number. \ \

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

\ Interval \	\ $\"minus$ \	\ $\"minus$ \
\ Test Value \	\ $\"x$ \	\ $\"x$ \
\ Sign of f\\'(x) \	\ $\"f$ \	\ $\"f$ \
\ Conclusion \	\ Decreasing \	\ Increasing \

$\"\"$

Therefore f is increasing on the interval $\"left$ and decreasing on the interval $\"left$ .