Short Answer
This proof demonstrates that if a and b are nonzero integers, we can manipulate the equation a/b + x = c/d to isolate x as x = (cb – ad) / bd. Since both the numerator and denominator are products of integers, x is confirmed to be a rational number.
Step 1: Understanding the Variables
In this proof, we are working with nonzero integers: a, b, c, and d. These integers will be integral to our calculations. Specifically, we start with the ratio a/b which represents a rational number. The objective is to manipulate this expression to solve for x, while keeping our focus on maintaining rationality throughout the process.
Step 2: Setting Up the Equation
The equation starts with adding the rational number a/b to an unknown x, leading us to the equation: a/b + x = c/d. We want to isolate x to demonstrate that it is also a rational number. To do this, we will subtract a/b from both sides of the equation, enabling us to express x in terms of c/d and a/b.
Step 3: Isolating x and Deriving the Final Equation
After rearranging the equation, we arrive at: x = c/d – a/b. To combine these fractions, we need a common denominator, which is bd. Thus, we manipulate the equation to find: x = (cb – ad) / bd. As both the numerator (cb – ad) and the denominator (bd) are products of integers, we conclude that x must indeed be a rational number.