Solve the problem.
-Let $f ( x ) = x ^ { 2 } + 15 x$. Find all values $x$ for which $f ( x ) = - 54$.
A) $0 , - 54$
B) 9,6
C) $- \frac { 5 } { 18 } , - \frac { 1 } { 54 }$
D) $- 9 , - 6$

Question

Quizplus · Accepted Answer

To find the values of $x$ for which $f(x) = -54$, we substitute $-54$ for $f(x)$ in the given equation and solve for $x$:$$x^2 + 15x = -54$$$$x^2 + 15x + 54 = 0$$Factoring the quadratic equation, we get:$$(x + 9)(x + 6) = 0$$Setting each factor equal to zero gives us the solutions:$$x + 9 = 0 \Rightarrow x = -9$$$$x + 6 = 0 \Rightarrow x = -6$$Therefore, the correct values of $x$ are $-9$ and $-6$.

Solve the Problem f(x)=x2+15xf ( x ) = x ^ { 2 } + 15 xf(x)=x2+15x

Solve the Problem $f ( x ) = x ^ { 2 } + 15 x$