Questions: Homework 5.3 - Rational Function
Question 2, 5.3.17
Find the domain of the following rational function.
H(x)=-8 x^2/(x-7)(x+2)
The domain is
(Type your answer in interval notation. Use integers or fractions for any numbers in the expression.)
Transcript text: Homework 5.3 - Rational Function
Question 2, 5.3.17
Find the domain of the following rational function.
\[
H(x)=\frac{-8 x^{2}}{(x-7)(x+2)}
\]
The domain is $\square$
(Type your answer in interval notation. Use integers or fractions for any numbers in the expression.)
Solution
Solution Steps
To find the domain of the rational function \( H(x) = \frac{-8x^2}{(x-7)(x+2)} \), we need to determine the values of \( x \) for which the function is defined. The function is undefined where the denominator is zero. Therefore, we need to find the values of \( x \) that make \( (x-7)(x+2) = 0 \).
Solution Approach
Identify the values of \( x \) that make the denominator zero.
Exclude these values from the domain.
Express the domain in interval notation.
Step 1: Identify the Values that Make the Denominator Zero
To find the domain of the rational function \( H(x) = \frac{-8x^2}{(x-7)(x+2)} \), we first identify the values of \( x \) that make the denominator zero. The denominator is \((x-7)(x+2)\).
Step 2: Solve for the Zeros of the Denominator
We solve the equation \((x-7)(x+2) = 0\) to find the values of \( x \) that make the denominator zero:
\[
(x-7)(x+2) = 0
\]
\[
x - 7 = 0 \quad \text{or} \quad x + 2 = 0
\]
\[
x = 7 \quad \text{or} \quad x = -2
\]
Step 3: Exclude the Zeros from the Domain
The function \( H(x) \) is undefined at \( x = 7 \) and \( x = -2 \). Therefore, we exclude these values from the domain.
Step 4: Express the Domain in Interval Notation
The domain of \( H(x) \) is all real numbers except \( x = 7 \) and \( x = -2 \). In interval notation, this is expressed as:
\[
(-\infty, -2) \cup (-2, 7) \cup (7, \infty)
\]