Solve the Problem $f ( x ) = - x ^ { 2 } + 4 x$

question 73

Multiple Choice

Solve the problem.
-Let $f ( x ) = - x ^ { 2 } + 4 x$ . Find all values $x$ for which $f ( x ) = - 21$ .

• A) 4,0
• B) \(7 , - 3\)
• C) \(- 7,3\)
• D) \(\frac { 4 } { 21 } , \frac { 1 } { - 21 }\)

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