Answer:
![f(x)=-x^2-4x+21](https://img.qammunity.org/2022/formulas/mathematics/high-school/agw15443o6adyy5cz4dqgo5o6xpwe4487m.png)
Explanation:
The given equation is :
f left parenthesis x right parenthesis equals negative x squared minus 4 x plus 21.
We need to rewrite this equation in faceted format.
The general form of a quadratic equation is given by :
![f(x)=ax^2+bx+c](https://img.qammunity.org/2022/formulas/mathematics/college/h5km1kti3vki8irt22yd035ipzjtxbq9zu.png)
We have,
a = -1, b = -4 and c = 21
Substitute all the values,
![f(x)=-x^2-4x+21](https://img.qammunity.org/2022/formulas/mathematics/high-school/agw15443o6adyy5cz4dqgo5o6xpwe4487m.png)
So, the required equation is equal to
.