given $f(x) = -x^2 - 5x - 9$, find $f(-9)$

Explanation:

Step1: Substitute ( x = -9 ) into ( f(x) )

Substitute ( x = -9 ) into the function ( f(x) = -x^2 - 5x - 9 ), we get ( f(-9) = -(-9)^2 - 5\times(-9) - 9 ).

Step2: Calculate each term

First, calculate ( (-9)^2 = 81 ), so ( -(-9)^2 = -81 ). Then, ( -5\times(-9) = 45 ). Now the expression becomes ( -81 + 45 - 9 ).

Step3: Simplify the expression

Calculate ( -81 + 45 = -36 ), then ( -36 - 9 = -45 ).

Answer:

( -45 )