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 into the function: Replace every occurrence of [tex]\( x \)[/tex] in the function with 3. So, the expression becomes:
[tex]\[
f(3) = -5(3)^2 - 3 + 20
\][/tex]

2. Calculate each part separately:
- Compute [tex]\( 3^2 \)[/tex]:
[tex]\[
3^2 = 9
\][/tex]
- Multiply by [tex]\(-5\)[/tex]:
[tex]\[
-5 \times 9 = -45
\][/tex]

3. Continue with the calculation:
- Add [tex]\(-3\)[/tex] to [tex]\(-45\)[/tex]:
[tex]\[
-45 - 3 = -48
\][/tex]

4. Add 20 to the result:
[tex]\[
-48 + 20 = -28
\][/tex]

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