Question: how to solve for domain and range in set notation
f(x)= 4x+1/x-7
1. **State the problem:** Find the domain and range of the function $$f(x) = \frac{4x+1}{x-7}$$ in set notation.
2. **Find the domain:** The domain is all real numbers $$x$$ for which the function is defined.
- The denominator $$x-7$$ cannot be zero because division by zero is undefined.
- So, set $$x-7 \neq 0$$ which gives $$x \neq 7$$.
- Therefore, the domain is all real numbers except $$7$$.
- In set notation, the domain is $$\{x \in \mathbb{R} \mid x \neq 7\}$$.
3. **Find the range:** The range is all possible values of $$f(x)$$.
- Let $$y = \frac{4x+1}{x-7}$$.
- Solve for $$x$$ in terms of $$y$$:
$$y = \frac{4x+1}{x-7}$$
Multiply both sides by $$x-7$$:
$$y(x-7) = 4x + 1$$
$$yx - 7y = 4x + 1$$
Rearrange terms:
$$yx - 4x = 7y + 1$$
Factor $$x$$:
$$x(y - 4) = 7y + 1$$
$$x = \frac{7y + 1}{y - 4}$$
- For $$x$$ to be defined, the denominator $$y - 4 \neq 0$$, so $$y \neq 4$$.
- Therefore, the range is all real numbers except $$4$$.
- In set notation, the range is $$\{y \in \mathbb{R} \mid y \neq 4\}$$.
4. **Final answer:**
- Domain: $$\{x \in \mathbb{R} \mid x \neq 7\}$$
- Range: $$\{y \in \mathbb{R} \mid y \neq 4\}$$