What is the extreme f(x)=x^3-9x^2-21x+9 ?

The extreme f(x)=x^3-9x^2-21x+9 is Maximum(-1,20),Minimum(7,-236)

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extreme f(x)=x^3-9x^2-21x+9

extreme

Maximum (- 1, 20), Minimum (7, - 236)

Solution steps

f^{'} (x) = 3 x^{2} - 18 x - 21

Find intervals:

Increasing

: - \infty < x < - 1,

Decreasing

: - 1 < x < 7,

Increasing

: 7 < x < \infty

Plug

x = - 1

into

x^{3} - 9 x^{2} - 21 x + 9 : 20

Maximum (- 1, 20)

Plug

x = 7

into

x^{3} - 9 x^{2} - 21 x + 9 : - 236

Minimum (7, - 236)

Maximum (- 1, 20), Minimum (7, - 236)

What is the extreme f(x)=x^3-9x^2-21x+9 ?
The extreme f(x)=x^3-9x^2-21x+9 is Maximum(-1,20),Minimum(7,-236)