Find the Critical Number(s), If Any, of the Function $f ( x ) = x ^ { 3 } - 21 x + 4$

question 58

Multiple Choice

Find the critical number(s) , if any, of the function $f ( x ) = x ^ { 3 } - 21 x + 4$ .

• A) 4
• B) \(- 4\)
• C) \(\pm \sqrt { 7 }\)
• D) \(\pm 7\)