Answer:
[tex]f(x)=-x^2-4x+21[/tex]
Step-by-step 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 :
[tex]f(x)=ax^2+bx+c[/tex]
We have,
a = -1, b = -4 and c = 21
Substitute all the values,
[tex]f(x)=-x^2-4x+21[/tex]
So, the required equation is equal to [tex]f(x)=-x^2-4x+21[/tex].