Answer to Question #26689 in Algebra for Jackie

Question

Not sure on how to do. Find the intervals where f is increasing and intervals where f is decreasing.
2x^2 -12x + 19

Answer 1

F(x) = 2x² -12x + 19

Let's find the derivative of F(x) with respect to x:

F'(x) = 4x - 12

Now let's find zeros of the derivative:

F'(x) = 0 ==> x = 3

The intervals of sign constancy are

F'(x)<0, if x<3
F'(x)>0, if x>3

Therefore, F is decreasing on the interval (-∞,3) and increasing on the interval (3,+∞).