Chapter 7: Problem 53
Solve the given equations involving fractions. $$\frac{1}{2 x}-\frac{3}{4}=\frac{1}{2 x+3}$$
Short Answer
Expert verified
The solutions are \(x = \frac{1}{2}\) and \(x = -2\).
Step by step solution
01
Eliminate Fractions
To solve the equation \( \frac{1}{2x} - \frac{3}{4} = \frac{1}{2x+3} \), first eliminate the fractions by finding a common denominator. The denominators are \(2x\), \(4\), and \(2x+3\). The common denominator is \(4(2x)(2x+3)\). Multiply every term by this common denominator to clear the fractions.
02
Simplify the Equation
After multiplying every term by the common denominator, the equation simplifies to \(4(2x+3) - 3(2x)(2x+3) = 4(2x)\). Expand each term: \(8x + 12 - 12x^2 - 18x = 8x\).
03
Rearrange Terms
Collect like terms on one side of the equation: \(-12x^2 - 18x + 8x + 12 = 8x\). Simplify to \(-12x^2 - 10x + 12 = 8x\).
04
Solve for x
Move all terms to one side of the equation, \(-12x^2 - 10x + 12 - 8x = 0\), simplifying to \(-12x^2 - 18x + 12 = 0\). Factor the quadratic equation: \(-6(2x^2 + 3x - 2) = 0\). Further factor to \(-6(2x - 1)(x + 2) = 0\).
05
Find Solutions for x
The solutions to \(-6(2x - 1)(x + 2) = 0\) are \(2x - 1 = 0\) (i.e., \(x = \frac{1}{2}\)) and \(x + 2 = 0\) (i.e., \(x = -2\)). Check each solution in the original equation.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Fractions
Fractions represent parts of a whole, often using a numerator (top number) and a denominator (bottom number). In this exercise, we dealt with several fractions, such as \( \frac{1}{2x} \), \( \frac{3}{4} \), and \( \frac{1}{2x+3} \). These fractions make equations more complex, so eliminating them is often the first step in solving such equations.
Working with fractions typically involves steps like:
Working with fractions typically involves steps like:
- Identifying the least common denominator, which helps align the fractions for addition, subtraction, or elimination.
- Converting fractions to have the common denominator if needed.
- Adding, subtracting, or otherwise manipulating these fractions to simplify the equation.
Common Denominator
The concept of a common denominator is a core component when dealing with equations involving fractions. It allows us to write the fractions with equivalent terms for easy arithmetic manipulation. In our example, the equation \( \frac{1}{2x} - \frac{3}{4} = \frac{1}{2x+3} \) included different denominators: \(2x\), \(4\), and \(2x+3\).
Finding the common denominator involves:
Finding the common denominator involves:
- Identifying all unique denominators in the equation.
- Determining a common multiple of all these denominators, often by multiplying them together.
Quadratic Equation
A quadratic equation is any equation that can be rearranged to the form \(ax^2 + bx + c = 0\), where \(a\), \(b\), and \(c\) are constants. In our solution, after clearing the fractions and simplifying, we ended with a quadratic equation \(-12x^2 - 18x + 12 = 0\).
This form is crucial because:
This form is crucial because:
- It indicates the equation will have two solutions or roots.
- It's a well-known form making it easier to apply various solving techniques like factoring or using the quadratic formula.
Factoring
Factoring is a mathematical process used to simplify expressions or solve equations. Specifically, it involves expressing a polynomial as a product of simpler polynomials or numbers. In our solution, we eventually factored \(-12x^2 - 18x + 12 = 0\) to \(-6(2x-1)(x+2) = 0\).
The factoring process includes:
The factoring process includes:
- Looking for common factors in all terms.
- Using patterns such as the difference of squares or trinomial squares.
- Breaking the quadratic trinomial into a product of two binomials, as was done here.