Chapter 5: Problem 15
In \(3-14\) , use the quadratic formula to find the roots of each equation. Irrational roots should be written in simplest radical form. $$ x^{2}-6 x+3=0 $$
Short Answer
Expert verified
The roots are \(x = 3 + \sqrt{6}\) and \(x = 3 - \sqrt{6}\).
Step by step solution
01
Identify the coefficients
The given quadratic equation is \(x^2 - 6x + 3 = 0\). Identify the coefficients \(a\), \(b\), and \(c\) for the quadratic formula \(ax^2+bx+c=0\). Here, \(a = 1\), \(b = -6\), and \(c = 3\).
02
Write the quadratic formula
The quadratic formula is \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). This formula is used to find the roots of any quadratic equation of the form \(ax^2+bx+c=0\).
03
Calculate the discriminant
The discriminant is the part under the square root in the quadratic formula, \(b^2 - 4ac\). Calculate it using the identified coefficients: \((-6)^2 - 4(1)(3) = 36 - 12 = 24\).
04
Apply the quadratic formula
Substitute the values \(a\), \(b\), and the discriminant into the quadratic formula. This gives: \[x = \frac{-(-6) \pm \sqrt{24}}{2(1)} = \frac{6 \pm \sqrt{24}}{2}\]
05
Simplify the radical and divide
Simplify the irrational part: \(\sqrt{24} = \sqrt{4 \times 6} = 2\sqrt{6}\). Substitute back:\[x = \frac{6 \pm 2\sqrt{6}}{2}\]Simplify by dividing each term by 2:\[x = 3 \pm \sqrt{6}\]
06
Write the roots
Finally, the rational roots of the quadratic equation \(x^2 - 6x + 3 = 0\) are \(x = 3 + \sqrt{6}\) and \(x = 3 - \sqrt{6}\).
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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. They represent polynomial equations of degree two and generally have the form \( ax^2 + bx + c = 0 \). This type of equation can graphically represent parabolas, which means they open upwards or downwards on a coordinate plane.
To solve a quadratic equation, several methods can be used, such as factoring, completing the square, or using the quadratic formula. Each method provides a way to find the values of \( x \) that satisfy the equation.
To solve a quadratic equation, several methods can be used, such as factoring, completing the square, or using the quadratic formula. Each method provides a way to find the values of \( x \) that satisfy the equation.
- **Factoring** involves expressing the quadratic as a product of two binomials.
- **Completing the square** transforms the equation so that one side is a perfect square trinomial.
- **The quadratic formula** is a powerful tool that can find roots for any quadratic equation, typically used when other methods are not straightforward.
- two distinct real roots
- one real root (a double root)
- or two complex roots
Discriminant
The discriminant plays a crucial role in understanding the nature of the solutions of a quadratic equation. It is found under the square root symbol in the quadratic formula and is constructed as \( b^2 - 4ac \). This value helps determine how many and what type of roots a quadratic equation has.
When the discriminant is:
When the discriminant is:
- **Positive**: There are two distinct real roots. This means the parabola crosses the x-axis at two points.
- **Zero**: There is one real root. The parabola touches the x-axis at one point. This root is called a double root.
- **Negative**: There are no real roots, but two complex roots. The parabola doesn't intersect the x-axis.
Radical Simplification
Radical simplification is about simplifying the square root component in the quadratic formula to its simplest form. To simplify \( \sqrt{24} \), we can break down the number inside the square root into its prime factors.
Here are the steps:
Here are the steps:
- Identify the perfect squares within 24. We know that \( 4 \) is a perfect square, and it fits into 24 to produce \( 24 = 4 \times 6 \).
- Simplify \( \sqrt{24} \) using this factorization: \( \sqrt{24} = \sqrt{4 \times 6} = \sqrt{4} \times \sqrt{6} \).
- Since \( \sqrt{4} = 2 \), the expression simplifies to \( 2\sqrt{6} \).