Select the correct answer.

Which expression is equivalent to [tex]\frac{(x-1)^2}{x^2-x-12} \cdot \frac{x^2+x-6}{x^2-6x+5}[/tex] if no denominator equals zero?

A. [tex]\frac{x^2-5+2}{x^2-9x+20}[/tex]

B. [tex]\frac{x^2+x-2}{x^2-x-20}[/tex]

C. [tex]\frac{x^2-3x+2}{x^2-20}[/tex]

D. [tex]\frac{x^2+3x+2}{x^2+x-20}[/tex]



Answer :

Sure! Let's find the equivalent expression to [tex]\(\frac{(x-1)^2}{x^2-x-12} \cdot \frac{x^2+x-6}{x^2-6x+5}\)[/tex].

First, let's factorize the given fractions wherever possible:

### Numerator of the First Fraction:
[tex]\((x-1)^2\)[/tex] is already a simplified expression.

### Denominator of the First Fraction:
[tex]\[x^2 - x - 12\][/tex]
To factorize [tex]\(x^2 - x - 12\)[/tex]:
[tex]\[x^2 - x - 12 = (x-4)(x+3)\][/tex]

### Numerator of the Second Fraction:
[tex]\[x^2 + x - 6\][/tex]
To factorize [tex]\(x^2 + x - 6\)[/tex]:
[tex]\[x^2 + x - 6 = (x-2)(x+3)\][/tex]

### Denominator of the Second Fraction:
[tex]\[x^2 - 6x + 5\][/tex]
To factorize [tex]\(x^2 - 6x + 5\)[/tex]:
[tex]\[x^2 - 6x + 5 = (x-1)(x-5)\][/tex]

We can plug these factorizations back into our original multiplication of fractions:

[tex]\[ \frac{(x-1)^2}{x^2 - x - 12} \cdot \frac{x^2 + x - 6}{x^2 - 6x + 5} \][/tex]

Substituting the factorizations:

[tex]\[ \frac{(x-1)^2}{(x-4)(x+3)} \cdot \frac{(x-2)(x+3)}{(x-1)(x-5)} \][/tex]

Next, we multiply the numerators and the denominators:

[tex]\[ \frac{(x-1)^2 (x-2)(x+3)}{(x-4)(x+3)(x-1)(x-5)} \][/tex]

We can cancel common factors in the numerator and the denominator:

- [tex]\((x-1)\)[/tex] cancels with [tex]\((x-1)\)[/tex] in the numerator, leaving [tex]\((x-1)\)[/tex] in the numerator.
- [tex]\((x+3)\)[/tex] cancels with [tex]\((x+3)\)[/tex] in the numerator.

Thus, we're left with:

[tex]\[ \frac{(x-1) (x-2)}{(x-4)(x-5)} \][/tex]

Simplifying:

Thus, the equivalent expression would be:

[tex]\[ \frac{(x-1)(x-2)}{(x-4)(x-5)} \][/tex]

Let’s expand the simplified fraction to compare it with the options:

[tex]\[ \frac{(x-1)(x-2)}{(x-4)(x-5)} = \frac{x^2 - 3x + 2}{x^2 - 9x + 20} \][/tex]

Therefore, the final equivalent expression is:

[tex]\[ \frac{x^2 - 3x + 2}{x^2 - 9x + 20} \][/tex]

Comparing this with the given options, the correct answer is:

[tex]\[ \boxed{\frac{x^2 - 3 x + 2}{x^2 - 9 x + 20}} \][/tex]

Thus, the correct option is:

C. [tex]\(\frac{x^2 - 3x + 2}{x^2 - 20}\)[/tex]