Chapter 6: Problem 48
Solve each equation. See Examples I through 9. (A few exercises are linear equations.) $$ x^{2}+15 x=0 $$
Short Answer
Expert verified
The solutions to the equation are \( x = 0 \) and \( x = -15 \).
Step by step solution
01
Identify the Type of Equation
Recognize that the given equation \( x^2 + 15x = 0 \) is a quadratic equation. Quadratic equations are in the form \( ax^2 + bx + c = 0 \). Here, \( a = 1 \), \( b = 15 \), and \( c = 0 \).
02
Factor the Equation
Since the equation can be factored, write it as a product of terms. Factor out the common variable \( x \):\[ x(x + 15) = 0 \]
03
Solve Each Factor
Set each factor equal to zero and solve for \( x \). This gives us two equations: \( x = 0 \) and \( x + 15 = 0 \).
04
Solve for Each Solution
Solve the second equation: \( x + 15 = 0 \) becomes \( x = -15 \).
05
List the Solutions
Combine the solutions from each factor to list all possible values of \( x \). The solutions are \( x = 0 \) and \( x = -15 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Factoring Quadratic Equations
Factoring is a very handy method for solving quadratic equations, especially when they can be simplified into a product of simpler expressions. A quadratic equation like \( x^2 + 15x = 0 \) can be factored easily because it lacks a constant term. This means we can extract a common factor from both terms, making the solution more approachable.Here's how factoring works in this case:
- First, recognize that both terms in the equation, \( x^2 \) and \( 15x \), share a common factor, \( x \).
- Factor out the \( x \) from the equation, which transforms \( x^2 + 15x = 0 \) into \( x(x + 15) = 0 \).
Solving Equations through Factoring
Once you've factored the equation, you've laid the groundwork for finding solutions. With the equation \( x(x + 15) = 0 \), you have two simpler equations ready to solve: \( x = 0 \) and \( x + 15 = 0 \).To solve these equations, apply these steps:
- Set each factor equal to zero. This stems from the zero-product property, which states that if a product of factors equals zero, at least one of the factors must be zero.
- The first equation, \( x = 0 \), is already solved.
- The second factor, \( x + 15 = 0 \), can be re-arranged to find \( x = -15 \) by subtracting 15 from both sides.
Understanding Quadratic Equations in Algebra
Quadratic equations are a fundamental component of algebra, characterized by the general form \( ax^2 + bx + c = 0 \). The solutions to these equations are often referred to as 'roots' or 'zeros'.Here are some important aspects:
- Quadratics can often be solved through several methods including factoring, using the quadratic formula, or completing the square.
- Factoring is typically the first method to try when the quadratic can be easily expressed as a product of simpler factors.
- The degree of the equation (which is 2 for quadratics) indicates the number of solutions you should expect. Therefore, \( x^2 + 15x = 0 \) will have two solutions, which we found to be \( x = 0 \) and \( x = -15 \).