Recall that we can add or subtract two rational expressions by using their Least Common Denominator (LCD).
See solution.
Practice makes perfect
Recall that we can only add or subtract two rational expressions if they have a common denominator. If this is not the case, we can use the Least Common Denominator (LCD).
The Least Common Denominator (LCD) of two rational expressions is the product of the prime factors, each raised to the greatest power that occurs in any of the expressions denominators.
To find the LCD we need to factor the denominators of both expressions into their prime factors. Once we have found the LCD we can expand the rational expressions to rewrite them with a common denominator. Then, we can add or subtract the numerators as needed. Let's see an example.
The LCD for this case would be 2* x* (x-5). To rewrite each expression with the LCD we can expand the fractions by using the factors that their denominators lack from the LCD.
