Chapter 9: Problem 13
Solve each equation using the quadratic formula. Simplify irrational solutions, if possible. $$x^{2}-2 x-10=0$$
Short Answer
Expert verified
The solutions to the equation are \(x = 1+ \sqrt{11}\) and \(x = 1 - \sqrt{11}\)
Step by step solution
01
Identify a, b, and c
From the given quadratic equation \(x^{2}-2 x-10=0\) , identify the values of \(a\), \(b\), and \(c\) as follows: \(a = 1\), \(b = -2\), \(c = -10\)
02
Substitute in the Quadratic Formula
Substitute the values of \(a\), \(b\), and \(c\) into the quadratic formula: \(x = \frac{-(-2) \pm \sqrt{(-2)^{2} - 4(1)(-10)}}{2(1)}\)
03
Calculate the Discriminant
Calculate the value under the square root, known as the discriminant: \((-2)^{2} - 4(1)(-10) = 4 + 40 = 44\)
04
Apply the Square Root and Simplify
Apply the square root to the discriminant and simplify the equation: \(x = \frac{2 \pm \sqrt{44}}{2}\). Now divide each term in the numerator by 2 to get \(x = 1 \pm \sqrt{11}\)
05
Final Answer
So the solutions to the equation \(x^{2}-2 x-10=0\) are \(x = 1+ \sqrt{11}\) and \(x = 1 - \sqrt{11}\)
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Solving Quadratic Equations
Quadratic equations are mathematical expressions of the form \( ax^2 + bx + c = 0 \), where \( a \), \( b \), and \( c \) are constants. To solve these equations, one widely used approach is the Quadratic Formula, which is a universal formula for finding the roots (solutions) of quadratic equations.
You can use the formula:
Remember:
You can use the formula:
- \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \)
Remember:
- \( b^2 - 4ac \) under the square root sign is called the discriminant, and it plays a crucial role in determining the nature of the roots.
- The \( \pm \) symbol indicates that there are usually two solutions.
Discriminant
The discriminant is a key part of the quadratic formula, represented by \( b^2 - 4ac \). It determines the nature of the roots for the quadratic equation. By evaluating the discriminant's value, you can ascertain characteristics about the solutions:
For example, when solving the equation \( x^2 - 2x - 10 = 0 \), the discriminant is calculated as follows:
- If the discriminant is positive, two distinct real roots exist.
- If the discriminant is zero, both roots are real and equal, which means there's exactly one solution.
- If the discriminant is negative, there are no real solutions, but two complex ones.
For example, when solving the equation \( x^2 - 2x - 10 = 0 \), the discriminant is calculated as follows:
- Using \( a = 1 \), \( b = -2 \), and \( c = -10 \), the discriminant formula gives \( (-2)^2 - 4(1)(-10) = 4 + 40 = 44 \).
- Since 44 is positive, it signifies that there are two distinct real roots.
Simplifying Square Roots
Simplifying square roots can often clarify the final solution to a quadratic equation. After applying the quadratic formula, you might end up with a square root that isn't immediately simple. Breaking down the square root involves finding its prime factors or simplifying it to its simplest radical form.
Here's how to simplify a square root such as \( \sqrt{44} \):
Here's how to simplify a square root such as \( \sqrt{44} \):
- Express 44 as a product of prime factors: \( 44 = 4 \times 11 \).
- Since \( \sqrt{4} = 2 \), you can simplify \( \sqrt{44} \) to \( 2\sqrt{11} \).
- Thus, the expression \( \frac{2 \pm \sqrt{44}}{2} \) simplifies to \( \frac{2 \pm 2\sqrt{11}}{2} \), which breaks down further to \( 1 \pm \sqrt{11} \) after dividing each term by 2.