f(x)=−3x2+12x−11 Step 1 of 2 : Find all values of x that correspond to horizontal tangent lines. Select "None" if the function does not have any values of x that correspond to horizontal tangent lines.

corresponds to a horizontal line tangent to .

Step-by-step explanation:

Let , its first derivative represents a formula to determine the slope of lines tangent to a given point of the curve and slopes of horizontal tangent line corresponds to those values of such that .

We obtain the first derivative and equalize it to zero:

And solve it for :

corresponds to a horizontal line tangent to .

answer: what in the world is this

step-by-step explanation: