Consider the equation below. $($If an answer does not exist, enter DNE.$)$

f$($x$)=$ x$312$x$227$x $+9$

$($a$)$

Find the interval$($s$)$ on which f is increasing. $($Enter your answer using interval notation.$)$

Good work.

Find the interval$($s$)$ on which f is decreasing. $($Enter your answer using interval notation.$)$

Amazing work.

$($b$)$

Find the local minimum and maximum values of f$.$

local minimum value$$

local maximum value$$