Chapter 0: Problem 69
Solve using any method. $$3 p^{2}-9 p+1=0$$
Short Answer
Expert verified
The solutions are \(p = \frac{9 + \sqrt{69}}{6}\) and \(p = \frac{9 - \sqrt{69}}{6}\).
Step by step solution
01
Identify the Coefficients
The given quadratic equation is \(3p^2 - 9p + 1 = 0\). Here, the coefficients are: \(a = 3\), \(b = -9\), and \(c = 1\).
02
Use the Quadratic Formula
The quadratic formula is \(p = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). Apply this formula using the identified coefficients: \(a = 3\), \(b = -9\), and \(c = 1\).
03
Calculate the Discriminant
The discriminant is the part inside the square root of the quadratic formula: \(b^2 - 4ac\). Calculate it: \((-9)^2 - 4 \times 3 \times 1 = 81 - 12 = 69\).
04
Compute the Roots
Using the quadratic formula: \(p = \frac{-(-9) \pm \sqrt{69}}{2 \times 3}\). Simplify: \(p = \frac{9 \pm \sqrt{69}}{6}\). So, the roots are \(p = \frac{9 + \sqrt{69}}{6}\) and \(p = \frac{9 - \sqrt{69}}{6}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Coefficients
When working with quadratic equations, identifying the coefficients is a crucial first step. A quadratic equation is typically written in the form: \[ ax^2 + bx + c = 0 \]Here, the letters \(a\), \(b\), and \(c\) represent the coefficients of the terms in the equation. Each coefficient has a specific role:
- \(a\): The coefficient of the squared term, \(x^2\).
- \(b\): The coefficient of the linear term, \(x\).
- \(c\): The constant term, which is a number without any variable attached.
- \(a = 3\)
- \(b = -9\)
- \(c = 1\)
Quadratic Formula
The quadratic formula is a powerful tool for solving quadratic equations. It is given by:\[p = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]This formula can always be used to find the roots of any quadratic equation, regardless of whether they are real or complex. The formula consists of different parts:
- \(-b\): The opposite of the linear coefficient.
- \(\pm\): Indicates that there are usually two solutions, one taking the plus and the other the minus in the equation.
- Square Root: Involves the discriminant, \(b^2 - 4ac\), which we will discuss next.
- \(2a\): Represents the denominator that multiplies the coefficient \(a\).
Discriminant
The discriminant is the part of the quadratic formula that lies under the square root, and it plays a significant role in determining the nature of the roots. It is computed as:\[b^2 - 4ac\]The value of the discriminant gives us insights into the roots:
- If positive: The equation has two distinct real roots.
- If zero: The equation has exactly one real root (a repeated root).
- If negative: The equation has two complex roots.
Roots
The roots of a quadratic equation are the solutions for the variable \(p\) that satisfy the equation. Using the quadratic formula, the roots can be found by evaluating:\[p = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]After calculating the discriminant and substituting it into the formula, the roots for the equation \(3p^2 - 9p + 1 = 0\) can be calculated as:\[p = \frac{9 \pm \sqrt{69}}{6}\]This computation results in two roots:
- \(p = \frac{9 + \sqrt{69}}{6}\)
- \(p = \frac{9 - \sqrt{69}}{6}\)