Chapter 5: Problem 6
Solve each equation using the Quadratic Formula. $$ 2 x^{2}+3 x-5=0 $$
Short Answer
Expert verified
The solutions to the equation 2x^2 + 3x - 5 = 0 are x = 1 and x = -2.5.
Step by step solution
01
Identify the coefficients
In the quadratic equation of the form ax^2 + bx + c = 0, identify the values of a, b, and c. For the equation 2x^2 + 3x - 5 = 0, the coefficients are a = 2, b = 3, and c = -5.
02
Write down the Quadratic Formula
The Quadratic Formula to find the roots of a quadratic equation ax^2 + bx + c = 0 is given by x = (-b ± √(b^2 - 4ac)) / (2a).
03
Plug the coefficients into the formula
Substitute the identified values into the Quadratic Formula: x = (-(3) ± √((3)^2 - 4(2)(-5))) / (2(2)).
04
Simplify under the square root
First calculate the discriminant: (3)^2 - 4(2)(-5) = 9 + 40 = 49.
05
Calculate the values of x
Now, plug the discriminant back into the formula and simplify: x = (-3 ± √49) / 4. This gives two solutions: x = (-3 + 7) / 4 = 1 and x = (-3 - 7) / 4 = -2.5.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Formula
The Quadratic Formula is a powerful tool for solving quadratic equations, which are equations of the form \( ax^2 + bx + c = 0 \). This formula provides a straightforward method for finding the roots of any quadratic equation. To apply the formula, you first need to identify the coefficients \( a \), \( b \), and \( c \) from the equation:
The General Quadratic Formula is: \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \). In this structure, the '±' symbol indicates that the equation has two solutions, commonly referred to as roots. By substituting the coefficients into this formula, you can solve for \( x \) to find the roots of the quadratic equation.
The General Quadratic Formula is: \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \). In this structure, the '±' symbol indicates that the equation has two solutions, commonly referred to as roots. By substituting the coefficients into this formula, you can solve for \( x \) to find the roots of the quadratic equation.
Discriminant
The term under the square root in the Quadratic Formula, \( b^2 - 4ac \), is known as the discriminant. It is crucial in determining the nature and number of roots a quadratic equation will have. Based on the value of the discriminant:
- If the discriminant is positive, there are two distinct real roots.
- If the discriminant is zero, there is exactly one real root (also called a repeated or double root).
- If the discriminant is negative, there are no real roots, but two complex roots.
Roots of Quadratic Equations
Roots of quadratic equations are the values of \( x \) that make the equation \( ax^2 + bx + c = 0 \) true. These are the solutions obtained after applying the Quadratic Formula. As demonstrated in our example, using \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), you arrive at two values for \( x \). Plugging in the discriminant \( \sqrt{49} \) and coefficients into the equation gives us: \( x = \frac{-3 \pm 7}{4} \), resulting in the two solutions \( x = 1 \) and \( x = -2.5 \). These solutions represent the x-intercepts or the points where the parabola represented by the quadratic equation crosses the x-axis.
Simplifying Expressions
Simplifying expressions is a fundamental step in solving quadratic equations using the Quadratic Formula. It involves arithmetic operations such as addition, subtraction, multiplication, and finding square roots. To keep simplification manageable:
- Always calculate the discriminant first.
- Perform any necessary squares and multiplications before dealing with the subtraction or addition.
- Use the calculated discriminant to simplify the square root term.
- Finally, divide as needed to get the x values which are the roots of the equation.