Chapter 8: Problem 12
Use the discriminant to determine the number and type of solutions for each equation. Do not solve. \(6 x^{2}-5 x-6=0\)
Short Answer
Expert verified
The equation has two distinct real solutions.
Step by step solution
01
Identify coefficients
The general form of a quadratic equation is \(ax^2 + bx + c = 0\). For the given equation \(6x^2 - 5x - 6 = 0\), identify the coefficients: \(a = 6\), \(b = -5\), \(c = -6\).
02
Write the discriminant formula
The discriminant \(D\) of a quadratic equation \(ax^2 + bx + c = 0\) is given by the formula \(D = b^2 - 4ac\). This formula helps to determine the number and types of solutions.
03
Substitute the coefficients into the formula
Substitute \(a = 6\), \(b = -5\), and \(c = -6\) into the discriminant formula: \(D = (-5)^2 - 4 imes 6 imes (-6)\).
04
Compute the discriminant
Calculate the discriminant: \(D = 25 - 4 imes 6 imes (-6) = 25 + 144 = 169\).
05
Determine the nature of solutions
Based on the discriminant value: if \(D > 0\), there are two distinct real solutions; if \(D = 0\), there is one real solution; and if \(D < 0\), there are two complex solutions. Here, \(D = 169\), which is greater than 0, indicating there are two distinct real solutions.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding the Discriminant
The discriminant is a key concept in solving quadratic equations, often represented by the symbol \(D\). It provides valuable information about the nature of the solutions of a quadratic equation without having to solve it. For any quadratic equation of the form \(ax^2 + bx + c = 0\), the discriminant is calculated using the formula: \(D = b^2 - 4ac\).
Understanding its role is crucial:
Understanding its role is crucial:
- **\(D > 0\)**: The equation has two distinct real solutions. This means the parabola intersects the x-axis at two points.
- **\(D = 0\)**: There's exactly one real solution. Here, the parabola touches the x-axis at only one point, known as a repeated root.
- **\(D < 0\)**: The solutions are complex and not real, meaning the parabola doesn't intersect the x-axis at any point.
Real Solutions of Quadratic Equations
When we talk about real solutions in the context of a quadratic equation, we're referring to the values of \(x\) that actually make the equation true in terms of real numbers. This is distinctly different from non-real (complex) solutions, which involve imaginary numbers.
Using the discriminant as a guide:
Using the discriminant as a guide:
- If \(D > 0\), two distinct real numbers satisfy the equation. This is often what we expect in typical real-world scenarios where inputs and outputs are measurable quantities.
- When \(D = 0\), a single real number makes the equation true. This situation can also be interpreted as the equation having a repeated or double root.
Identifying Coefficients in Quadratic Equations
Coefficients in a quadratic equation provide essential clues about the equation's shape and position. These are the numerical factors before variables in the standard form \(ax^2 + bx + c = 0\). In this format:
- **\(a\)**: This is the leading coefficient, which affects the parabola's width and direction (upward or downward opening).
- **\(b\)**: Known as the linear coefficient, it influences the parabola's axis of symmetry and its position along the x-axis.
- **\(c\)**: This constant term affects the parabola's vertical position, determining where it crosses the y-axis.