College

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

A. [tex]-28[/tex]
B. [tex]-13[/tex]
C. 62
D. 64

Answer :

To find [tex]\( f(3) \)[/tex] for the given function [tex]\( f(x) = -5x^2 - x + 20 \)[/tex], we will substitute [tex]\( x = 3 \)[/tex] into the function and simplify the expression step by step:

1. Substitute [tex]\( x = 3 \)[/tex] into the function:

[tex]\[
f(3) = -5(3)^2 - (3) + 20
\][/tex]

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

[tex]\[
3^2 = 9
\][/tex]

3. Multiply [tex]\(-5\)[/tex] by [tex]\( 9 \)[/tex]:

[tex]\[
-5 \times 9 = -45
\][/tex]

4. Substitute [tex]\(-45\)[/tex] into the function:

[tex]\[
f(3) = -45 - 3 + 20
\][/tex]

5. Add [tex]\(-45\)[/tex] and [tex]\(-3\)[/tex]:

[tex]\[
-45 - 3 = -48
\][/tex]

6. Add [tex]\(-48\)[/tex] and [tex]\(20\)[/tex]:

[tex]\[
-48 + 20 = -28
\][/tex]

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