1. **State the problem:** We are given two functions:
$$f(x) = 3x - 30$$
$$g(x) = x^2 - x - 90$$
We need to find the function \(\frac{f}{g}(x)\) and determine its domain.
2. **Formula used:** The division of two functions is defined as:
$$\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)}$$
The domain of \(\frac{f}{g}(x)\) includes all values of \(x\) where \(g(x) \neq 0\).
3. **Find \(\frac{f}{g}(x)\):**
$$\frac{f}{g}(x) = \frac{3x - 30}{x^2 - x - 90}$$
4. **Factor numerator and denominator:**
Numerator:
$$3x - 30 = 3(x - 10)$$
Denominator:
Factor \(x^2 - x - 90\): find two numbers that multiply to \(-90\) and add to \(-1\).
These are \(-10\) and \(9\), so:
$$x^2 - x - 90 = (x - 10)(x + 9)$$
5. **Simplify the fraction:**
$$\frac{3(x - 10)}{(x - 10)(x + 9)}$$
Cancel the common factor \(x - 10\) (noting \(x \neq 10\) to avoid division by zero):
$$\frac{3\cancel{(x - 10)}}{\cancel{(x - 10)}(x + 9)} = \frac{3}{x + 9}$$
6. **Domain:**
The original denominator \(g(x) = (x - 10)(x + 9)\) cannot be zero, so:
$$x - 10 \neq 0 \Rightarrow x \neq 10$$
$$x + 9 \neq 0 \Rightarrow x \neq -9$$
Therefore, the domain of \(\frac{f}{g}(x)\) is all real numbers except \(x = 10\) and \(x = -9\).
**Final answers:**
$$\left(\frac{f}{g}\right)(x) = \frac{3}{x + 9}$$
Domain: \(x \neq 10, -9\)
Function Division E3A1Dd
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