Question

Could anyone help me with this question? Thank you!

Answer 1

Answer:

C

Step-by-step explanation:

We want to simplify the rational expression:

$\displaystyle \frac{n^4-11n^2+30}{n^4-7n^2+10}$

First, we can factor both the numerator and the denominator. This yields:

$\displaystyle =\frac{(n^2-6)(n^2-5)}{(n^2-2)(n^2-5)}$

Cancel like terms:

$\displaystyle =\frac{(n^2-6)}{(n^2-2)}$

However, since we canceled a term from our expression, we must place restrictions in order to stay true to the original expression.

Rational expressions are undefined whenever the denominator equals 0. The denominator is (before canceling):

$(n^2-2)(n^2-5)=0$

Solve for n. By the zero product property:

$n^2-2=0\text{ and } n^2-5=0$

Therefore:

$n^2=2\text{ and } n^2=5$

By taking the square root of both sides (since we are taking an even root, it is required to have plus/minus):

$n=\pm\sqrt{2}\text{ and } n=\pm\sqrt5$

Therefore, our fully simplified expression is:

$\displaystyle \frac{n^2-6}{n^2-2}\, ,n\neq \pm\sqrt5, \pm\sqrt2$

Hence, our answer is C!