Chapter 3: Problem 7
Find the \(x\)- and \(y\)-intercepts of the rational function. $$t(x)=\frac{x^{2}-x-2}{x-6}$$
Short Answer
Expert verified
The x-intercepts are (2,0) and (-1,0); the y-intercept is (0, 1/3).
Step by step solution
01
Find the x-intercept
To find the x-intercept, set the numerator of the function equal to zero, since the x-intercept occurs where the function crosses the x-axis ( t(x) = 0). Here, we solve for x in the equation:\[ x^2 - x - 2 = 0 \]We can factor this equation to find its roots:\[ (x - 2)(x + 1) = 0 \]Set each factor equal to zero:\[ x - 2 = 0 \quad \text{or} \quad x + 1 = 0 \]Thus, \( x = 2 \) or \( x = -1 \). These are the x-intercepts: (2,0) and (-1,0).
02
Find the y-intercept
To find the y-intercept, set x equal to zero in the original function and solve for t(x), since the y-intercept occurs where the function crosses the y-axis. Substitute:\[ t(0) = \frac{0^2 - 0 - 2}{0 - 6} = \frac{-2}{-6} = \frac{1}{3} \]The y-intercept is at (0, 1/3).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding X-Intercept
The x-intercept of a function is the point where the graph of the function crosses the x-axis. For rational functions like \( t(x)=\frac{x^{2}-x-2}{x-6} \), the x-intercept can be found by setting the numerator equal to zero. This is because at the x-intercept, the value of the function is zero, meaning:
- The function equals zero at the x-intercept.
- The graph crosses the x-axis, so \( t(x) = 0 \).
Investigating Y-Intercept
The y-intercept is a fundamental concept in graphing functions. It is the point where the function's graph crosses the y-axis. To find the y-intercept of a rational function, set \( x = 0 \) in the function. This will simplify to the point where the function's output is the y-coordinate:
- The y-intercept occurs when \( x = 0 \).
- For our function, \( t(x)=\frac{x^{2}-x-2}{x-6} \), substitute \( x = 0 \).
Factoring Quadratics
Factoring quadratic equations is crucial for solving them, especially when working with rational functions. The goal is to rewrite the quadratic in a product form that reveals the solutions. Given the quadratic \( x^2 - x - 2 \), finding its factors involves these steps:
- If possible, find two numbers that multiply to the constant term (-2) but add up to the middle coefficient (-1).
- For this equation, the numbers are -2 and 1.
- Rewrite the quadratic as the product: \( (x - 2)(x + 1) \).
Finding Intercepts in Rational Functions
Both x- and y-intercepts provide essential information about a function's graph. For rational functions like \( t(x)=\frac{x^{2}-x-2}{x-6} \), intercepts indicate where the function crosses the axes, giving crucial insight into its behavior:
- X-intercepts: Occur where the function equals zero, found by setting the numerator zero. Solve \( x^2 - x - 2 = 0 \) to find \( x = 2 \) and \( x = -1 \).
- Y-intercept: Occurs where \( x = 0 \). Substitute \( x = 0 \) into the function to find it at (0, 1/3).