Answer:

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 :

We have,
a = -1, b = -4 and c = 21
Substitute all the values,

So, the required equation is equal to
.