College

Given the function [tex]$f(x) = -5x^2 - x + 20$[/tex], find [tex]$f(3)$[/tex].

A. -28
B. -13
C. 62
D. 64

Answer :

To find [tex]\( f(3) \)[/tex] for the function [tex]\( f(x) = -5x^2 - x + 20 \)[/tex], follow these steps:

1. Substitute 3 for [tex]\( x \)[/tex] in the function.
We have:
[tex]\[
f(3) = -5(3)^2 - 3 + 20
\][/tex]

2. Calculate [tex]\( 3^2 \)[/tex].
[tex]\[
3^2 = 9
\][/tex]

3. Multiply by -5.
[tex]\[
-5 \times 9 = -45
\][/tex]

4. Substitute the calculated value back into the expression.
[tex]\[
f(3) = -45 - 3 + 20
\][/tex]

5. Perform the addition and subtraction.
[tex]\[
-45 - 3 = -48
\][/tex]
[tex]\[
-48 + 20 = -28
\][/tex]

Thus, the value of [tex]\( f(3) \)[/tex] is [tex]\(-28\)[/tex].