Find the [tex][tex]$LCD$[/tex][/tex] of the following expressions. Write [tex]$LCD$[/tex] in factored form.

[tex]\[ \frac{2}{q^2 - 3q - 54} \][/tex]
[tex]\[ \frac{8q}{q^2 - 11q + 18} \][/tex]

[tex]$LCD$:[/tex]



Answer :

To find the Least Common Denominator (LCD) of the given rational expressions [tex]\(\frac{2}{q^2 - 3q - 54}\)[/tex] and [tex]\(\frac{8q}{q^2 - 11q + 18}\)[/tex], we follow these steps:

1. Factor the denominators of each expression.

2. Identify the highest power of each distinct factor that appears in the denominators.

3. Multiply these factors together to find the LCD.

### Step 1: Factor the denominators

First, we factor the quadratic expressions in the denominators.

For [tex]\(\frac{2}{q^2 - 3q - 54}\)[/tex]:

We need to factor the quadratic expression [tex]\(q^2 - 3q - 54\)[/tex].

To factor it, we look for two numbers that multiply to [tex]\(-54\)[/tex] and add up to [tex]\(-3\)[/tex].

These numbers are [tex]\(-9\)[/tex] and [tex]\(6\)[/tex].

[tex]\[ q^2 - 3q - 54 = (q - 9)(q + 6) \][/tex]

So, the denominator of the first expression factors to [tex]\((q - 9)(q + 6)\)[/tex].

For [tex]\(\frac{8q}{q^2 - 11q + 18}\)[/tex]:

We need to factor the quadratic expression [tex]\(q^2 - 11q + 18\)[/tex].

To factor it, we look for two numbers that multiply to [tex]\(18\)[/tex] and add up to [tex]\(-11\)[/tex].

These numbers are [tex]\(-9\)[/tex] and [tex]\(-2\)[/tex].

[tex]\[ q^2 - 11q + 18 = (q - 9)(q - 2) \][/tex]

So, the denominator of the second expression factors to [tex]\((q - 9)(q - 2)\)[/tex].

### Step 2: Identify the highest power of each distinct factor

We now have the factored forms of the denominators:

- [tex]\((q - 9)(q + 6)\)[/tex]
- [tex]\((q - 9)(q - 2)\)[/tex]

The distinct factors are [tex]\(q - 9\)[/tex], [tex]\(q + 6\)[/tex], and [tex]\(q - 2\)[/tex].

The highest power of each factor present in the denominators is:

- [tex]\(q - 9\)[/tex] appears once in both denominators.
- [tex]\(q + 6\)[/tex] appears once in the first denominator.
- [tex]\(q - 2\)[/tex] appears once in the second denominator.

### Step 3: Multiply these factors to find the LCD

The Least Common Denominator is the product of these highest powers:

[tex]\[ \text{LCD} = (q - 9)(q + 6)(q - 2) \][/tex]

### Final Answer:

The Least Common Denominator (LCD) of the given expressions [tex]\(\frac{2}{q^2 - 3q - 54}\)[/tex] and [tex]\(\frac{8q}{q^2 - 11q + 18}\)[/tex] in factored form is:

[tex]\[ \boxed{(q - 9)(q + 6)(q - 2)} \][/tex]