Question

given the function $f(x) = -5x^2 - x + 20$, find $f(3)$.\
\bigcirc\\ -28\
\bigcirc\\ -13\
\bigcirc\\ 62\
\bigcirc\\ 64

Explanation:

Step1: Substitute \( x = 3 \) into the function

We have the function \( f(x)=-5x^{2}-x + 20 \). When we substitute \( x = 3 \), we get \( f(3)=-5\times(3)^{2}-3 + 20 \).

Step2: Calculate the power term

First, calculate \( (3)^{2}=9 \). Then the expression becomes \( f(3)=-5\times9-3 + 20 \).

Step3: Calculate the multiplication

Calculate \( -5\times9=-45 \). So now the expression is \( f(3)=-45-3 + 20 \).

Step4: Calculate the addition and subtraction

First, \( -45-3=-48 \), then \( -48 + 20=-28 \).

Answer:

\(-28\) (corresponding to the option: -28)