Chapter 12: Problem 127
$$\text { Solve: } \frac{x+2}{4 x+3}=\frac{1}{x}$$
Short Answer
Expert verified
The solution is \(x = 3\) and \(x = -1\).
Step by step solution
01
Cross Multiplication
Cross multiply the fractions to eliminate the denominator, which gives: \(x(x+2) = 4x + 3\).
02
Expansion
Expand the left-hand side, resulting in \(x^2 + 2x = 4x + 3\).
03
Rearrange
Rearrange to set the equation equal to zero, resulting in \(x^2 + 2x - 4x - 3 = 0\). Simplify to \(x^2 - 2x - 3 = 0\).
04
Factor the Quadratic
Factorize the equation as \((x - 3)(x + 1) = 0\).
05
Solve for 'x'
Since the product of two factors is zero, at least one of them must be zero. This gives us two solutions: \(x - 3 = 0\) and \(x + 1 = 0\), giving \(x = 3\) and \(x = -1\) respectively.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Cross Multiplication
Cross multiplication is a technique often used to solve equations involving two fractions set equal to each other. By cross-multiplying, you eliminate the fractions, resulting in a simpler equation. In this process, the numerator of one fraction is multiplied by the denominator of the other, and vice versa.
For example, in the equation \(\frac{x+2}{4x+3} = \frac{1}{x}\), cross multiplying gives \(x(x+2) = 4x + 3\).
For example, in the equation \(\frac{x+2}{4x+3} = \frac{1}{x}\), cross multiplying gives \(x(x+2) = 4x + 3\).
- This operation clears the denominators, allowing you to focus solely on a straightforward polynomial equation.
- Notice that this is a crucial step because it sets the stage for further manipulation, like expanding and rearranging terms.
Quadratic Equations
Once cross multiplication has been applied, you may find yourself dealing with a quadratic equation. A quadratic equation is any equation that can be written in the form \(ax^2 + bx + c = 0\), where \(a\), \(b\), and \(c\) are constants, and \(x\) represents an unknown.
In the exercise, after expanding and rearranging terms, the equation \(x^2 - 2x - 3 = 0\) is revealed. This is a textbook quadratic equation.
In the exercise, after expanding and rearranging terms, the equation \(x^2 - 2x - 3 = 0\) is revealed. This is a textbook quadratic equation.
- Quadratic equations are significant because they appear frequently in various areas of math and science.
- To solve these equations, you can use several methods such as factoring, completing the square, or applying the quadratic formula.
Factoring Polynomials
Factoring polynomials involves expressing a polynomial as a product of its simpler factors. It’s a key method for solving quadratic equations when they can be easily factorized.
In the quadratic equation \(x^2 - 2x - 3 = 0\), we factor the expression into \((x - 3)(x + 1) = 0\). This step is vital because it breaks down the equation into simpler components, each of which can be solved separately.
In the quadratic equation \(x^2 - 2x - 3 = 0\), we factor the expression into \((x - 3)(x + 1) = 0\). This step is vital because it breaks down the equation into simpler components, each of which can be solved separately.
- Factoring involves finding the roots, or values of \(x\), that make the equation true by setting each factor equal to zero.
- In our equation, the factors are \(x - 3\) and \(x + 1\). Setting these equal to zero gives \(x = 3\) and \(x = -1\).
Rearranging Equations
Rearranging equations is a common practice in algebra that involves moving terms around to achieve a particular form - often to set the equation to zero or isolate a variable.
In solving \(x^2 + 2x = 4x + 3\), rearranging steps included bringing all terms to one side, resulting in \(x^2 + 2x - 4x - 3 = 0\). This simplifies further to \(x^2 - 2x - 3 = 0\).
In solving \(x^2 + 2x = 4x + 3\), rearranging steps included bringing all terms to one side, resulting in \(x^2 + 2x - 4x - 3 = 0\). This simplifies further to \(x^2 - 2x - 3 = 0\).
- Rearranging makes the equation easier to solve by combining like terms and simplifying the expression.
- This step prepares the quadratic equation for either factoring, using the quadratic formula, or another solving method.