Multiply: [tex]\frac{a^2+8a+15}{a^2+7a+12} \cdot \frac{3a+12}{a^2-25}[/tex]

(a) [tex]\frac{3(a+5)}{a^2-25}[/tex]
(b) [tex]\frac{-3}{a+4}[/tex]
(c) [tex]\frac{3}{a-5}[/tex]



Answer :

Sure, let's go through the solution step-by-step.

1. Factor the Numerator and Denominator of the First Expression:
[tex]\[ \frac{a^2 + 8a + 15}{a^2 + 7a + 12} \][/tex]

The numerator [tex]\(a^2 + 8a + 15\)[/tex] can be factored as:
[tex]\[ (a + 3)(a + 5) \][/tex]

The denominator [tex]\(a^2 + 7a + 12\)[/tex] can be factored as:
[tex]\[ (a + 3)(a + 4) \][/tex]

So, the first expression becomes:
[tex]\[ \frac{(a + 3)(a + 5)}{(a + 3)(a + 4)} \][/tex]

2. Factor the Numerator and Denominator of the Second Expression:
[tex]\[ \frac{3a + 12}{a^2 - 25} \][/tex]

The numerator [tex]\(3a + 12\)[/tex] can be factored as:
[tex]\[ 3(a + 4) \][/tex]

The denominator [tex]\(a^2 - 25\)[/tex] can be factored as:
[tex]\[ (a - 5)(a + 5) \][/tex]

So, the second expression becomes:
[tex]\[ \frac{3(a + 4)}{(a - 5)(a + 5)} \][/tex]

3. Multiply the Two Factored Expressions:
[tex]\[ \left(\frac{(a + 3)(a + 5)}{(a + 3)(a + 4)}\right) \cdot \left(\frac{3(a + 4)}{(a - 5)(a + 5)}\right) \][/tex]

4. Cancel Out Common Factors:
- The [tex]\((a + 3)\)[/tex] terms cancel each other out.
- The [tex]\((a + 4)\)[/tex] terms cancel each other out.
- The [tex]\((a + 5)\)[/tex] terms cancel each other out.

We are left with:
[tex]\[ \frac{3}{(a - 5)} \][/tex]

5. Simplified Result:
[tex]\[ \frac{3}{a - 5} \][/tex]

Therefore, the simplified product of the given expressions is:
[tex]\[ \frac{3}{a - 5} \][/tex]

So, the correct answer is:
[tex]\[ \boxed{\frac{3}{a - 5}} \][/tex]