Find all real numbers $k$ such that $x^4+kx^3+x^2+4kx+16=0$ is true for exactly one real number $x = r$.  Enter all the possible values of $k,$ separated by commas.
Question:
Find all real numbers $k$ such that $x^4+kx^3+x^2+4kx+16=0$ is true for exactly one real number $x = r$.  Enter all the possible values of $k,$ separated by commas.
Answer:
Let's think step by step.

user
\frac{9}{4}, -\frac{9}{4}
Find all real numbers $k$ such that $x^4+kx^3+x^2+4kx+16=0$ is true for exactly one real number $x = r$.  Enter all the possible values of $k,$ separated by commas.
train