Answer :
To find [tex]\( f(3) \)[/tex] for the function [tex]\( f(x) = -5x^2 - x + 20 \)[/tex], we substitute [tex]\( x = 3 \)[/tex] into the function and calculate the result step-by-step.
1. Start with the function:
[tex]\( f(x) = -5x^2 - x + 20 \)[/tex].
2. Substitute [tex]\( x = 3 \)[/tex]:
[tex]\( f(3) = -5(3)^2 - (3) + 20 \)[/tex].
3. Calculate [tex]\( 3^2 \)[/tex]:
[tex]\( 3^2 = 9 \)[/tex].
4. Replace in the function:
[tex]\( f(3) = -5 \times 9 - 3 + 20 \)[/tex].
5. Calculate [tex]\(-5 \times 9\)[/tex]:
[tex]\(-5 \times 9 = -45\)[/tex].
6. Substitute back to the expression:
[tex]\( f(3) = -45 - 3 + 20 \)[/tex].
7. Perform the addition and subtraction:
First, combine [tex]\(-45\)[/tex] and [tex]\(-3\)[/tex]:
[tex]\(-45 - 3 = -48\)[/tex].
8. Then add 20:
[tex]\(-48 + 20 = -28\)[/tex].
Therefore, [tex]\( f(3) = -28 \)[/tex].
1. Start with the function:
[tex]\( f(x) = -5x^2 - x + 20 \)[/tex].
2. Substitute [tex]\( x = 3 \)[/tex]:
[tex]\( f(3) = -5(3)^2 - (3) + 20 \)[/tex].
3. Calculate [tex]\( 3^2 \)[/tex]:
[tex]\( 3^2 = 9 \)[/tex].
4. Replace in the function:
[tex]\( f(3) = -5 \times 9 - 3 + 20 \)[/tex].
5. Calculate [tex]\(-5 \times 9\)[/tex]:
[tex]\(-5 \times 9 = -45\)[/tex].
6. Substitute back to the expression:
[tex]\( f(3) = -45 - 3 + 20 \)[/tex].
7. Perform the addition and subtraction:
First, combine [tex]\(-45\)[/tex] and [tex]\(-3\)[/tex]:
[tex]\(-45 - 3 = -48\)[/tex].
8. Then add 20:
[tex]\(-48 + 20 = -28\)[/tex].
Therefore, [tex]\( f(3) = -28 \)[/tex].
