Skip to main content
Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 2, Problem 39

Solve each equation. 2x2+x-15 = 0

Verified step by step guidance
1
Identify the quadratic equation in standard form: \$2x^{2} + x - 15 = 0$.
Recall the quadratic formula: \(x = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a}\), where \(a\), \(b\), and \(c\) are coefficients from the equation \(ax^{2} + bx + c = 0\).
Determine the coefficients: \(a = 2\), \(b = 1\), and \(c = -15\).
Calculate the discriminant: \(\Delta = b^{2} - 4ac = 1^{2} - 4 \times 2 \times (-15)\).
Substitute the values into the quadratic formula and simplify under the square root and the entire expression to find the two possible values of \(x\).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Quadratic Equations

A quadratic equation is a second-degree polynomial equation in the form ax² + bx + c = 0, where a ≠ 0. It represents a parabola when graphed and typically has two solutions, which can be real or complex numbers.
Recommended video:
05:35
Introduction to Quadratic Equations

Factoring Quadratic Expressions

Factoring involves rewriting a quadratic expression as a product of two binomials. This method is useful when the quadratic can be expressed as (mx + n)(px + q) = 0, allowing the use of the zero-product property to find solutions.
Recommended video:
06:08
Solving Quadratic Equations by Factoring

Zero-Product Property

The zero-product property states that if the product of two factors equals zero, then at least one of the factors must be zero. This principle is essential for solving equations after factoring, as it leads to setting each factor equal to zero to find the roots.
Recommended video:
3:49
Product, Quotient, and Power Rules of Logs