Chapter 11: Problem 5
Use the quadratic formula to solve each equation. These equations have real number solutions only. See Examples I through 3. $$ x^{2}-6 x+9=0 $$
Short Answer
Expert verified
The solution to the equation is \( x = 3 \).
Step by step solution
01
Identify the Quadratic Equation
The given equation is \( x^2 - 6x + 9 = 0 \). This equation is in the standard form of a quadratic equation, which is \( ax^2 + bx + c = 0 \), where \( a = 1 \), \( b = -6 \), and \( c = 9 \).
02
Recall the Quadratic Formula
The quadratic formula for solving equations of the form \( ax^2 + bx + c = 0 \) is \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \).
03
Substitute Values into the Quadratic Formula
Substitute \( a = 1 \), \( b = -6 \), and \( c = 9 \) into the quadratic formula: \( x = \frac{-(-6) \pm \sqrt{(-6)^2 - 4 \cdot 1 \cdot 9}}{2 \cdot 1} \).
04
Simplify the Expression
First, compute inside the square root: \( (-6)^2 = 36 \) and \( 4 \cdot 1 \cdot 9 = 36 \). Therefore, \( b^2 - 4ac = 36 - 36 = 0 \). Substitute into the formula: \( x = \frac{6 \pm \sqrt{0}}{2} \).
05
Calculate the Final Result
Since \( \sqrt{0} = 0 \), the equation simplifies to \( x = \frac{6}{2} \). This gives \( x = 3 \). Since the discriminant \( b^2 - 4ac \) is zero, there is only one unique solution.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Equations
Quadratic equations are a fundamental part of algebra and are characterized by the presence of an unknown variable squared. These equations typically appear in the form of \( ax^2 + bx + c = 0 \), where \( a \), \( b \), and \( c \) are constants, and \( x \) represents the unknown value you need to solve for.
To tackle these equations, it's crucial to identify all the components properly:
To tackle these equations, it's crucial to identify all the components properly:
- \( a \): The coefficient of \( x^2 \). It determines the "width" and "direction" of the parabola when graphing the equation.
- \( b \): The coefficient of \( x \). It affects the position of the parabola along the x-axis.
- \( c \): The constant term. It shows where the parabola intersects the y-axis.
Solving Equations
When it comes to solving quadratic equations, the quadratic formula is a powerful tool. The quadratic formula is\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]and it provides the solutions to any quadratic equation by substituting the values of \( a \), \( b \), and \( c \) from the equation into this formula.
To use the formula:
To use the formula:
- Identify the values of \( a \), \( b \), and \( c \) from the equation.
- Substitute these values into the formula.
- Calculate inside the square root, known as the discriminant.
- Simplify the expression to find the value(s) of \( x \).
Discriminant
The discriminant in the quadratic formula is the expression \( b^2 - 4ac \), found inside the square root. It plays a critical role in determining the nature of the roots of the quadratic equation.
Understanding the discriminant helps to quickly establish:
Understanding the discriminant helps to quickly establish:
- If the discriminant is positive, \( b^2 - 4ac > 0 \), the equation has two distinct real roots.
- If the discriminant equals zero, \( b^2 - 4ac = 0 \), there is exactly one real root, indicating a repeated or double root.
- If the discriminant is negative, \( b^2 - 4ac < 0 \), the equation has no real roots, instead two complex conjugate roots.