13. [0.6/1 Points]
DETAILS PREVIOUS ANSWERS SCALCET9 3.1.059.EP. MY NOTES PRACTICE ANOTHER
Consider the following function.
y = $x^3 + 3x^2 - 9x + 6$
Find $y'(x)$.
y'(x) = $3x^2 + 6x - 9$
The graph of y(x) has a horizontal tangent line when y'(x) is equal to what value?
y'(x) = 0
Set y'(x) equal to the value above and solve for x. (Enter your answers as a comma-separated list.)
x = 1, -3
Find the points on the given curve where the tangent is horizontal.
smaller x-value (x, y) = (1, 1)
larger x-value (x, y) =