Solving Rational Equations: A Step-by-Step Guide

by Alex Johnson 49 views

When you first encounter an equation like 1x+2−1x+3=12\frac{1}{x+2}-\frac{1}{x+3}=\frac{1}{2}, it might look a little intimidating. These are called rational equations, and they involve fractions where the variable is in the denominator. But don't worry! By following a systematic approach, we can break down these problems into manageable steps and find the solution. The key to solving any rational equation is to eliminate the denominators, which allows us to work with a simpler algebraic expression. We'll be using our mathematics skills to conquer this challenge, transforming this complex fraction problem into something much more familiar, like a linear or quadratic equation that we know how to solve. Remember, practice makes perfect, and understanding the underlying principles will make you confident in tackling any rational equation that comes your way.

Understanding Rational Equations and Their Solutions

Let's dive deeper into what makes a rational equation unique and why our approach to solving them is so important. A rational equation is essentially an equation that contains one or more rational expressions. A rational expression is just a fraction where the numerator and denominator are polynomials. The variable, in this case 'x', appears in the denominator of at least one of these fractions. This is a crucial distinction because it means we must be mindful of values of 'x' that would make any denominator equal to zero. These values are called excluded values or restrictions, and they can never be solutions to our equation. If, after solving, we find that one of our potential solutions is an excluded value, we must discard it. It's like having a secret rule that certain numbers can't be part of the answer. In our specific problem, 1x+2−1x+3=12\frac{1}{x+2}-\frac{1}{x+3}=\frac{1}{2}, the excluded values are x=−2x = -2 and x=−3x = -3, because these values would cause the denominators (x+2)(x+2) and (x+3)(x+3) to become zero, leading to division by zero, which is undefined in mathematics. So, as we proceed, we'll keep these numbers in the back of our minds, ready to check our final answers against them. Understanding these restrictions is a fundamental part of mastering rational equations and ensures we find valid solutions.

Step 1: Find a Common Denominator

The first strategic move in solving 1x+2−1x+3=12\frac{1}{x+2}-\frac{1}{x+3}=\frac{1}{2} is to find a common denominator for all the fractions involved. This is a cornerstone technique in working with fractions, whether they contain variables or not. The goal here is to combine the fractions on the left side of the equation into a single fraction. To do this, we need to identify the least common multiple (LCM) of the denominators. In our case, the denominators are (x+2)(x+2), (x+3)(x+3), and 22. Since (x+2)(x+2) and (x+3)(x+3) are distinct linear expressions, and 22 is a constant, the least common denominator (LCD) will be the product of all these unique factors: 2(x+2)(x+3)2(x+2)(x+3). This might seem like it's making the equation more complex initially, but trust us, this is the critical step that sets us up for simplification. Once we have our LCD, we'll rewrite each fraction so that it has this common denominator. For the first fraction, 1x+2\frac{1}{x+2}, we need to multiply both the numerator and the denominator by 2(x+3)2(x+3). For the second fraction, 1x+3\frac{1}{x+3}, we multiply by 2(x+2)2(x+2). And for the constant term 12\frac{1}{2}, we multiply by (x+2)(x+3)(x+2)(x+3). This process ensures that all terms are on a