Adding or Subtracting Rational Expressions with Different Denominators
Here is the procedure for adding (or subtracting) fractions.
To Add or Subtract Rational Expressions That Have Different Denominators
Step 1 Find the LCD.
Step 2 Rewrite each rational expression with the LCD as the denominator.
Step 3 Add or subtract the numerators. The denominator stays the same.
Step 4 Reduce to lowest terms.
To factor 5x2 - 3x - 2:
â€¢ Find two integers whose product is 5(-2) = -10, and whose sum is -3. They are 2 and -5.
â€¢ Use these integers to rewrite 5x2 - 3x - 2 as 5x2 + 2x - 5x - 2.
â€¢ Factor by grouping. x(5x + 2) - 1(5x + 2) = (5x + 2)(x + 1)
To factor x2 + 5x - 6:
â€¢ Find two integers whose product is -6 and whose sum is 5. They are -1 and 6.
â€¢ Use these integers to write the factorization (x - 1)(x + 6).