1. **State the problem:** Find the domain and range of the function $$f(x) = \frac{7x}{9x - 1}$$.
2. **Find the domain:** The domain consists of all real numbers $x$ for which the function is defined. The function is undefined when the denominator is zero.
Set the denominator equal to zero and solve:
$$9x - 1 = 0$$
$$9x = 1$$
$$x = \frac{1}{9}$$
So, the function is undefined at $x = \frac{1}{9}$.
**Domain:** All real numbers except $x = \frac{1}{9}$.
3. **Find the range:** To find the range, solve for $x$ in terms of $y$ where $y = f(x)$:
$$y = \frac{7x}{9x - 1}$$
Multiply both sides by the denominator:
$$y(9x - 1) = 7x$$
Distribute $y$:
$$9xy - y = 7x$$
Group terms with $x$ on one side:
$$9xy - 7x = y$$
Factor out $x$:
$$x(9y - 7) = y$$
Solve for $x$:
$$x = \frac{y}{9y - 7}$$
The function is undefined when the denominator of this expression is zero:
$$9y - 7 = 0$$
$$9y = 7$$
$$y = \frac{7}{9}$$
So, $y = \frac{7}{9}$ is not in the range.
**Range:** All real numbers except $y = \frac{7}{9}$.
4. **Summary:**
- Domain: $\{x \in \mathbb{R} \mid x \neq \frac{1}{9}\}$
- Range: $\{y \in \mathbb{R} \mid y \neq \frac{7}{9}\}$
Domain Range Df29F4
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