Chapter 10: Problem 2
Use the quadratic formula to solve each of the following quadratic equations. $$x^{2}+3 x-4=0$$
Short Answer
Expert verified
The solutions are \(x = 1\) and \(x = -4\).
Step by step solution
01
Identify Coefficients
First, identify the coefficients from the quadratic equation \(x^2 + 3x - 4 = 0\). Here, \(a = 1\), \(b = 3\), and \(c = -4\).
02
Write the Quadratic Formula
The quadratic formula is \(x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{2a}\). This formula will be used to find the roots of the quadratic equation.
03
Calculate the Discriminant
Calculate the discriminant using the formula \(b^2 - 4ac\). For this equation, it is \(3^2 - 4(1)(-4)\), which simplifies to \(9 + 16 = 25\).
04
Apply the Quadratic Formula
Substitute the values of \(a\), \(b\), and \(c\) into the quadratic formula. With \(b = 3\) and discriminant \(= 25\), the formula becomes \(x = \frac{{-3 \pm \sqrt{25}}}{2(1)}\).
05
Simplify the Expression
Calculate the square root of the discriminant (\(\sqrt{25} = 5\)), and substitute back to get two solutions: \(x = \frac{{-3 + 5}}{2}\) and \(x = \frac{{-3 - 5}}{2}\).
06
Find the Solutions
Simplify further to find the solutions \(x = 1\) and \(x = -4\).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Equations
Quadratic equations are a fundamental concept in algebra, typically taking the form \(ax^2 + bx + c = 0\). These equations can model various real-world phenomena, such as projectile motion or optimization problems. The key components of a quadratic equation are:
- \(a\): the quadratic coefficient, which multiplies the \(x^2\) term
- \(b\): the linear coefficient, which multiplies the \(x\) term
- \(c\): the constant term, independent of \(x\)
Discriminant
The discriminant is a crucial part of the quadratic formula, given by \(b^2 - 4ac\). It provides insight into the types of roots a quadratic equation will have, without solving the equation:
- If the discriminant is positive, the equation has two distinct real roots.
- If it equals zero, there is exactly one real root, sometimes called a repeated or double root.
- If the discriminant is negative, the equation has two complex roots, which are conjugates of each other.
Roots of a Quadratic Equation
The roots of a quadratic equation are the solutions to the equation, where the graph of the quadratic function intersects the x-axis. These roots can be found using the quadratic formula: \(x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{2a}\). Let's break down the process:
- Plug in coefficients: Substitute the values of \(a\), \(b\), and \(c\) into the formula. For \(x^2 + 3x - 4 = 0\), \(a = 1\), \(b = 3\), \(c = -4\).
- Calculate using the discriminant: As we calculated earlier, \(b^2 - 4ac = 25\). This positive discriminant implies two real solutions.
- Apply the formula: Substitute these values to get \(x = \frac{{-3 \pm 5}}{2}\), producing two solutions from the positive and negative square root.
- Compute solutions: Simplifying gives \(x = 1\) and \(x = -4\).