Find the domain of the rational function. Then, write it in lowest terms.f(x)=6x52x2−8f\left(x\right)=\frac{6x^5}{2x^2-8}f(x)=2x2−86x5

{ x ∣ x ≠ 2 , − 2 } , f ( x ) = 3 x 5 x 2 − 4 {\left\lbrace x|x\ne2,-2\right\rbrace},f(x)=\frac{3x^5}{x^2-4} { x ∣ x  = 2 , − 2 } , f ( x ) = x 2 − 4 3 x 5

Find the domain of the rational function. Then, write it in lowest terms. f ( x ) = 6 x 5 2 x 2 − 8 f\left(x\right)=\frac{6x^5}{2x^2-8} f ( x ) = 2 x 2 − 8 6 x 5

In this problem, we're asked to find the domain of our rational function and then write it in lowest terms. Remember, we always want to find our domain before writing in lowest terms, so let's go ahead and start there. Now we want to take our denominator here, which is 2x squared minus 8, and set it equal to 0 to find our domain. So solving for x here, I'm going to go ahead and add 8 to both sides, leaving me with 2x squared is equal to 8. Then I'm going to go ahead and divide both sides by 2, leaving me with x squared equals 4. And then finally, my last step here in isolating x is taking the square root of both sides, which will leave me with x is equal to plus or minus the square root of 4, which we know is just 2. So this tells me that I have two numbers in my domain restriction, two numbers that would make my denominator 0 that x cannot be. So my domain is x such that x cannot be equal to positive 2 or negative 2, and there's my domain. Now that we have our domain, let's go ahead and focus on writing our function in lowest terms. So I'm going to go ahead and copy my function again down here just so that we can start fresh. F of x is equal to 6x to the 5th divided by 2x squared minus 8. Okay. Remember, we want to factor both the top and the bottom of our function, so let's go ahead and do that. Now for the numerator, it's not immediately obvious to me what I can factor here, so I'm gonna go ahead and start with the denominator. Now in the denominator, I see that I have a greatest common factor between these two terms of 2. So I'm gonna go ahead and pull out a 2 from each of them, leaving me with 2 times x squared minus 4. Now looking at my numerator, I see that I can also go ahead and pull out a 2 there because I know that that will cancel. So I'm gonna go ahead and pull out a 2 of my numerator as well. So pulling out that 2 leaves me with 2 times 3x to the power of 5. Now for my numerator, it doesn't look like I can factor anything else, and I could factor my denominator more, this x squared minus 4. I could actually factor into x+2 timesxminus2, but I can tell that that's not going to cancel with anything in my numerator so it's not really necessary here. So I'm just going to go ahead and cancel this 2 out of my function and that will leave me with 3x to the 5th as my numerator divided by x squared minus 4 and that is my function in lowest terms. 3x to the 5th divided by x squared minus 4 and we're done here. I'll see you in the next video.

Find the domain of the rational function. Then, write it in lowest terms. f ( x ) = 6 x 5 2 x 2 − 8 f\left(x\right)=\frac{6x^5}{2x^2-8} f ( x ) = 2 x 2 − 8 6 x 5

{ x ∣ x ≠ 2 , − 2 } , f ( x ) = 3 x 5 x 2 − 4 {\left\lbrace x|x\ne2,-2\right\rbrace},f(x)=\frac{3x^5}{x^2-4} { x ∣ x  = 2 , − 2 } , f ( x ) = x 2 − 4 3 x 5

{ x ∣ x ≠ 2 } , f ( x ) = 3 x 5 x 2 − 4 {\left\lbrace x|x\ne2\right\rbrace},f(x)=\frac{3x^5}{x^2-4} { x ∣ x  = 2 } , f ( x ) = x 2 − 4 3 x 5

{ x ∣ x ≠ 2 } , f ( x ) = 3 x 5 x 2 − 8 {\left\lbrace x|x\ne2\right\rbrace},f(x)=\frac{3x^5}{x^2-8} { x ∣ x  = 2 } , f ( x ) = x 2 − 8 3 x 5

0. Functions

Common Functions

Calculus

0. Functions

Common Functions

Struggling with Calculus?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

Find the domain of the rational function. Then, write it in lowest terms.
$f\left(x\right)=\frac{6x^5}{2x^2-8}$

${\left\lbrace x|x\ne2,-2\right\rbrace},f(x)=\frac{3x^5}{x^2-4}$

${\left\lbrace x|x\ne2,-2\right\rbrace},f(x)=\frac{6x^5}{2x^2-8}$

${\left\lbrace x|x\ne2\right\rbrace},f(x)=\frac{3x^5}{x^2-4}$

${\left\lbrace x|x\ne2\right\rbrace},f(x)=\frac{3x^5}{x^2-8}$

Verified step by step guidance

Identify the rational function: $ f(x) = \frac{6x^5}{2x^2 - 8} $. A rational function is defined for all real numbers except where the denominator is zero.

Set the denominator equal to zero to find the values that are not in the domain: $ 2x^2 - 8 = 0 $.

Solve the equation $ 2x^2 - 8 = 0 $ by first adding 8 to both sides to get $ 2x^2 = 8 $, then divide by 2 to obtain $ x^2 = 4 $.

Take the square root of both sides to find $ x = \pm 2 $. These are the values that make the denominator zero, so they are excluded from the domain.

Simplify the function by factoring the denominator: $ 2x^2 - 8 = 2(x^2 - 4) = 2(x - 2)(x + 2) $. The function in lowest terms is $ f(x) = \frac{3x^5}{x^2 - 4} $, and the domain is $ \{ x \mid x \neq 2, -2 \} $.

5:57m

Watch next

Master Graphs of Common Functions with a bite sized video explanation from Patrick

Start learning

Common Functions practice set

Problem sets built by lead tutors

Expert video explanations

Go to Practice