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------------------------------------------------ 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], we need to substitute [tex]\( x = 3 \)[/tex] into the function.

1. Start with the function:
[tex]\[
f(x) = -5x^2 - x + 20
\][/tex]

2. Substitute [tex]\( x = 3 \)[/tex] into the function:
[tex]\[
f(3) = -5(3)^2 - (3) + 20
\][/tex]

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

4. Multiply by [tex]\(-5\)[/tex]:
[tex]\[
-5 \times 9 = -45
\][/tex]

5. Continue with the expression:
[tex]\[
f(3) = -45 - 3 + 20
\][/tex]

6. Combine the terms:
- Start by adding [tex]\(-45\)[/tex] and [tex]\(-3\)[/tex]:
[tex]\[
-45 - 3 = -48
\][/tex]
- Then add 20:
[tex]\[
-48 + 20 = -28
\][/tex]

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