Problem 2: Evaluate the function [tex]f(x) = 3x^2 - 5x[/tex] at the following values:

1. [tex]f(-1)[/tex]
2. [tex]f(1)[/tex]
3. [tex]f(a)[/tex]
4. [tex]-f(a)[/tex]
5. [tex]f(a+h)[/tex]



Answer :

Sure! Let's evaluate the function [tex]\( f(x) = 3x^2 - 5x \)[/tex] at the specified values step-by-step.

### 1. Evaluate [tex]\( f(-1) \)[/tex]
To find [tex]\( f(-1) \)[/tex], substitute [tex]\( x = -1 \)[/tex] into the function:
[tex]\[ f(-1) = 3(-1)^2 - 5(-1) \][/tex]
Now calculate each term individually:
[tex]\[ 3(-1)^2 = 3 \cdot 1 = 3 \][/tex]
[tex]\[ -5(-1) = 5 \][/tex]
Combine these results:
[tex]\[ f(-1) = 3 + 5 = 8 \][/tex]

### 2. Evaluate [tex]\( f(1) \)[/tex]
To find [tex]\( f(1) \)[/tex], substitute [tex]\( x = 1 \)[/tex] into the function:
[tex]\[ f(1) = 3(1)^2 - 5(1) \][/tex]
Now calculate each term individually:
[tex]\[ 3(1)^2 = 3 \cdot 1 = 3 \][/tex]
[tex]\[ -5(1) = -5 \][/tex]
Combine these results:
[tex]\[ f(1) = 3 - 5 = -2 \][/tex]

### 3. Evaluate [tex]\( f(a) \)[/tex]
To find [tex]\( f(a) \)[/tex], substitute [tex]\( x = a \)[/tex] into the function:
[tex]\[ f(a) = 3a^2 - 5a \][/tex]

### 4. Evaluate [tex]\( -f(a) \)[/tex]
To find [tex]\( -f(a) \)[/tex], negate the expression for [tex]\( f(a) \)[/tex]:
[tex]\[ -f(a) = -(3a^2 - 5a) \][/tex]
Distribute the negative sign:
[tex]\[ -f(a) = -3a^2 + 5a \][/tex]

### 5. Evaluate [tex]\( f(a + h) \)[/tex]
To find [tex]\( f(a + h) \)[/tex], substitute [tex]\( x = a + h \)[/tex] into the function:
[tex]\[ f(a + h) = 3(a + h)^2 - 5(a + h) \][/tex]
Expand the squared term:
[tex]\[ (a + h)^2 = a^2 + 2ah + h^2 \][/tex]
So,
[tex]\[ 3(a + h)^2 = 3(a^2 + 2ah + h^2) = 3a^2 + 6ah + 3h^2 \][/tex]
Distribute and combine all terms:
[tex]\[ -5(a + h) = -5a - 5h \][/tex]
Combine these results together:
[tex]\[ f(a + h) = 3a^2 + 6ah + 3h^2 - 5a - 5h \][/tex]

Thus, the evaluation of the function [tex]\( f(x) = 3x^2 - 5x \)[/tex] at the specified values provides the following results:
1. [tex]\( f(-1) = 8 \)[/tex]
2. [tex]\( f(1) = -2 \)[/tex]
3. [tex]\( f(a) = 3a^2 - 5a \)[/tex]
4. [tex]\( -f(a) = -3a^2 + 5a \)[/tex]
5. [tex]\( f(a + h) = 3a^2 + 6ah + 3h^2 - 5a - 5h \)[/tex]