Consider the function f ( x ) = − 2 x 3 + 27 x 2 − 108 x + 9 . for this function there are three important open intervals: ( − [infinity] , a ) , ( a , b ) , and ( b , [infinity] ) where a and b are the critical numbers. find a and b

A=3 and B=6

Step-by-step explanation:

Increasing and Decreasing Intervals of Functions

Given f(x) as a real function and f'(x) its first derivative.

If f'(a)>0 the function is increasing in x=a

If f'(a)<0 the function is decreasing in x=a

If f'(a)=0 the function has a critical point in x=a

As we can see, the critical points may define open intervals where the function has different behaviors.

We have

Computing the first derivative:

We find the critical points equating f'(x) to zero

Simplifying by -6

We get the critical points

They define the following intervals

Thus A=3 and B=6

the simplified form is

step-by-step explanation:

we want to simplify the expression,

let us change the middle bar to a normal division sign to obtain,

we multiply the first fraction by the reciprocal of the second fraction to obtain,

we factor to obtain,

we cancel the common factors to get,

we simplify to get,

the correct answer is b

correct answer is b. 27/8

step-by-step explanation: