Chapter 0: Problem 7
Use the Quadratic Formula to find all real zeros of the second-degree polynomial. $$ 2 x^{2}+3 x-4 $$
Short Answer
Expert verified
The real zeros of the polynomial \(2 x^{2}+3 x-4\) are \(x = \frac{-3 + \sqrt{41}}{4}\) and \(x = \frac{-3 - \sqrt{41}}{4}\)
Step by step solution
01
Identify the coefficients
Identify the coefficients \(a\), \(b\), and \(c\) in the quadratic equation. For the given equation \(2x^2 + 3x - 4 = 0\), we have \(a = 2, b = 3, c = -4\)
02
The Quadratic Formula
Substitute the coefficients into the Quadratic Formula: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). For the given equation, this works out to \(x = \frac{-3 \pm \sqrt{3^2 - 4*2*(-4)}}{2*2}\)
03
Simplify the expression
Simplify the expression found in step 2: \(x = \frac{-3 \pm \sqrt{9 + 32}}{4}\), which simplifies further to \(x = \frac{-3 \pm \sqrt{41}}{4}\)
04
Find the roots
Find the two roots by solving the two equations \(x = \frac{-3 + \sqrt{41}}{4}\) and \(x = \frac{-3 - \sqrt{41}}{4}\)
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Second-Degree Polynomial
A second-degree polynomial is a type of polynomial that includes a term with the variable raised to the power of two. It is also known as a quadratic polynomial or trinomial. The general form of a second-degree polynomial is:
- \( ax^2 + bx + c \)
Real Zeros
Real zeros of a second-degree polynomial refer to the values of \( x \) that make the polynomial equal to zero. These values are also known as solutions or x-intercepts, and they occur where the graph of the polynomial crosses the x-axis.Finding these real zeros is often accomplished using several techniques:
- Factoring the polynomial, if possible
- Completing the square
- Using the Quadratic Formula
Quadratic Equation
A quadratic equation is an equation of the form \( ax^2 + bx + c = 0 \), where \( a \), \( b \), and \( c \) are known coefficients, and \( a eq 0 \). It is called a quadratic equation because it is an equation involving a square.The solutions to a quadratic equation are found using the Quadratic Formula:\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]This formula helps us find the values of \( x \) that satisfy the equation. It is derived from completing the square and provides a direct way to calculate the solutions. The expression under the square root sign, \( b^2 - 4ac \), is called the discriminant, and it plays a key role in determining the nature of the solutions. Understanding how to apply the Quadratic Formula is essential for solving quadratics, as it provides a reliable method to find the roots when other methods like factoring aren't feasible.
Roots of a Polynomial
The roots of a polynomial are the values of the variable that make the polynomial equal to zero. In the context of a quadratic equation, these roots are also referred to as the solutions of the equation or the x-intercepts of the graph.For a quadratic polynomial like \( 2x^2 + 3x - 4 \), the roots are found by setting the entire expression equal to zero and solving for \( x \). These roots can be real or complex, depending on the discriminant \( b^2 - 4ac \).In our case, we found two roots:
- \( x = \frac{-3 + \sqrt{41}}{4} \)
- \( x = \frac{-3 - \sqrt{41}}{4} \)