Chapter 9: Problem 62
\(n^{2}=10 n+8\)
Short Answer
Expert verified
\(n = 5 + \sqrt{33}\) or \(n = 5 - \sqrt{33}\)
Step by step solution
01
Set the Equation to Zero
Rewrite the given equation by bringing all terms to one side to set it to zero: \(n^{2} - 10n - 8 = 0\)
02
Identify Coefficients
Identify the coefficients from the quadratic equation in standard form \(an^{2} + bn + c = 0\). Here, \(a = 1\), \(b = -10\), and \(c = -8\).
03
Use the Quadratic Formula
The quadratic formula is \(n = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). Substitute the identified coefficients into this formula.
04
Calculate the Discriminant
Calculate the discriminant, \(b^2 - 4ac\): \((-10)^2 - 4(1)(-8) = 100 + 32 = 132\).
05
Compute the Solutions
Substitute the discriminant back into the quadratic formula to find the solutions for \(n\): \(n = \frac{10 \pm \sqrt{132}}{2} = \frac{10 \pm 2\sqrt{33}}{2} = 5 \pm \sqrt{33}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Formula
Quadratic equations can be solved using the quadratic formula, which is a powerful tool. It helps us find the values of the variable that make the equation true. The quadratic formula is: \[ n = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]Here, the symbols have specific meanings:
- is the coefficient of \(n^2\)
- is the coefficient of \(n\)
is the constant term
Discriminant Calculation
The discriminant is a key part of the quadratic formula that helps determine the nature of the roots of the quadratic equation. It is calculated using: \[ b^2 - 4ac \]
- If the discriminant is positive, the quadratic equation has two distinct real roots.
- If the discriminant is zero, the quadratic equation has exactly one real root, also known as a repeated or double root.
- If the discriminant is negative, the quadratic equation has two complex roots.
Standard Form of Quadratic Equation
A quadratic equation is usually expressed in the standard form: \[ax^2 + bx + c = 0\]To use the quadratic formula effectively, the equation must be in this form. Here’s how to convert any given quadratic equation to standard form:
- Move all terms to one side of the equation
- Arrange them in descending order of their degrees