What is the simplified form of the rational expression below?

[tex]\[ \frac{6x^2 - 54}{5x^2 + 15x} \][/tex]

A. [tex]\(\frac{6(x-3)}{5}\)[/tex]

B. [tex]\(\frac{6(x-3)}{5x}\)[/tex]

C. [tex]\(\frac{6(x+3)}{5}\)[/tex]

D. [tex]\(\frac{6(x+3)}{5x}\)[/tex]



Answer :

Let's simplify the given rational expression step by step.

The rational expression given is:
[tex]\[ \frac{6 x^2 - 54}{5 x^2 + 15 x} \][/tex]

First, let's factorize the numerator and the denominator separately.

### Step 1: Factorize the numerator
The numerator is [tex]\(6 x^2 - 54\)[/tex].

We can factor out the greatest common factor, which is [tex]\(6\)[/tex], from the numerator:
[tex]\[ 6 x^2 - 54 = 6 (x^2 - 9) \][/tex]

Notice that [tex]\(x^2 - 9\)[/tex] is a difference of squares, which can be further factored:
[tex]\[ x^2 - 9 = (x - 3)(x + 3) \][/tex]

Therefore, the factored form of the numerator is:
[tex]\[ 6 (x^2 - 9) = 6 (x - 3)(x + 3) \][/tex]

### Step 2: Factorize the denominator
The denominator is [tex]\(5 x^2 + 15 x\)[/tex].

We can factor out the greatest common factor, which is [tex]\(5 x\)[/tex], from the denominator:
[tex]\[ 5 x^2 + 15 x = 5 x (x + 3) \][/tex]

### Step 3: Write the rational expression with the factored numerator and denominator
Using the factored forms from Steps 1 and 2, the rational expression becomes:
[tex]\[ \frac{6 (x - 3)(x + 3)}{5 x (x + 3)} \][/tex]

### Step 4: Simplify the rational expression
We can cancel out the common factors in the numerator and denominator. Specifically, [tex]\((x + 3)\)[/tex] appears in both the numerator and the denominator:
[tex]\[ \frac{6 (x - 3) \cancel{(x + 3)}}{5 x \cancel{(x + 3)}} = \frac{6 (x - 3)}{5 x} \][/tex]

Thus, the simplified form of the rational expression is:
[tex]\[ \frac{6 (x - 3)}{5 x} \][/tex]

### Conclusion
The simplified form of the rational expression [tex]\(\frac{6 x^2 - 54}{5 x^2 + 15 x}\)[/tex] is:

[tex]\[ \boxed{\frac{6(x-3)}{5 x}} \][/tex]

So, the correct answer is:

B. [tex]\(\frac{6(x-3)}{5 x}\)[/tex]