Question

Find f plus g​, f minus g​, fg and StartFraction f Over g EndFraction
. Determine the domain for each function.
f left parenthesis x right parenthesis equals 3 x minus 7​, g left parenthesis x right parenthesis equals x minus 3
Question content area bottom
Part 1
left parenthesis f plus g right parenthesis left parenthesis x right parenthesis equals
  
enter your response here ​(Simplify your​ answer.)
Part 2
What is the domain of f plus g​?
A.
The domain of f plus g is StartSet nothing EndSet
  
. ​(Use a comma to separate answers as​ needed.)
B.
The domain of f plus g is
  
enter your response here. ​(Type your answer in interval​ notation.)
C.
The domain of f plus g is empty set.
Part 3
left parenthesis f minus g right parenthesis left parenthesis x right parenthesis equals
  
enter your response here ​(Simplify your​ answer.)
Part 4
What is the domain of f minus g​?
A.
The domain of f minus g is
  
enter your response here. ​(Type your answer in interval​ notation.)
B.
The domain of f minus g is StartSet nothing EndSet
  
. ​(Use a comma to separate answers as​ needed.)
C.
The domain of f minus g is empty set.
Part 5
left parenthesis fg right parenthesis left parenthesis x right parenthesis equals
  
enter your response here
​(Simplify your​ answer.)
Part 6
What is the domain of​ fg?
A.
The domain of fg is
  
enter your response here. ​(Type your answer in interval​ notation.)
B.
The domain of fg is StartSet nothing EndSet
  
. ​(Use a comma to separate answers as​ needed.)
C.
The domain of fg is empty set.
Part 7
left parenthesis StartFraction f Over g EndFraction right parenthesis left parenthesis x right parenthesis equals
  
enter your response here ​(Simplify your​ answer.)
Part 8
What is the domain of StartFraction f Over g EndFraction
​?
A.
The domain of StartFraction f Over g EndFraction
is
  
enter your response here. ​(Type your answer in interval​ notation.)
B.
The domain of StartFraction f Over g EndFraction
is StartSet nothing EndSet
  
. ​(Use a comma to separate answers as​ needed.)
C.
The domain of StartFraction f Over g EndFraction
is empty set.

Answers

GPT-4o mini
Let's solve each part step by step.

### Given:
- \( f(x) = 3x - 7 \)
- \( g(x) = x - 3 \)

### Part 1: \( (f + g)(x) \)
To find \( f + g \), we add the two functions:
\[
(f + g)(x) = f(x) + g(x) = (3x - 7) + (x - 3) = 3x - 7 + x - 3 = 4x - 10
\]
So,
\[
(f + g)(x) = 4x - 10
\]

### Part 2: Domain of \( f + g \)
The domain of \( f(x) \) and \( g(x) \) is all real numbers, so:
\[
\text{Domain of } (f + g) = (-\infty, \infty)
\]

### Part 3: \( (f - g)(x) \)
To find \( f - g \), we subtract \( g \) from \( f \):
\[
(f - g)(x) = f(x) - g(x) = (3x - 7) - (x - 3) = 3x - 7 - x + 3 = 2x - 4
\]
So,
\[
(f - g)(x) = 2x - 4
\]

### Part 4: Domain of \( f - g \)
Again, the domain of both functions is all real numbers:
\[
\text{Domain of } (f - g) = (-\infty, \infty)
\]

### Part 5: \( (fg)(x) \)
To find \( fg \), we multiply \( f \) and \( g \):
\[
(fg)(x) = f(x) \cdot g(x) = (3x - 7)(x - 3)
\]
Now expanding this:
\[
= 3x^2 - 9x - 7x + 21 = 3x^2 - 16x + 21
\]
So,
\[
(fg)(x) = 3x^2 - 16x + 21
\]

### Part 6: Domain of \( fg \)
The domain for the product of two polynomials is also all real numbers:
\[
\text{Domain of } fg = (-\infty, \infty)
\]

### Part 7: \( \left(\frac{f}{g}\right)(x) \)
For the quotient, we find \( \frac{f}{g} \):
\[
\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} = \frac{3x - 7}{x - 3}
\]

### Part 8: Domain of \( \frac{f}{g} \)
The function \( \frac{f}{g} \) is defined wherever \( g(x) \neq 0 \):
\[
g(x) = x - 3 = 0 \Rightarrow x = 3 \quad \text{is a point of discontinuity.}
\]
So, the domain in interval notation is:
\[
\text{Domain of } \frac{f}{g} = (-\infty, 3) \cup (3, \infty)
\]

### Summary of Answers
1. \( (f + g)(x) = 4x - 10 \)
2. Domain of \( f + g \): \((- \infty, \infty)\)
3. \( (f - g)(x) = 2x - 4 \)
4. Domain of \( f - g \): \((- \infty, \infty)\)
5. \( (fg)(x) = 3x^2 - 16x + 21 \)
6. Domain of \( fg \): \((- \infty, \infty)\)
7. \( \left(\frac{f}{g}\right)(x) = \frac{3x - 7}{x - 3} \)
8. Domain of \( \frac{f}{g} \): \((- \infty, 3) \cup (3, \infty)\)

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