1. Algebra 1 Glencoe McGraw-Hill JoAnn Evans
Math 8H
11-7
Rational Expressions
With
Unlike Denominators
Algebra Glencoe McGraw-Hill JoAnn Evans

2. Fractions Rational Expressions
You know that there has to be a common denominator when two fractions are added or subtracted. Rational expressions are no different.
Fractions Rational Expressions
Least Common Denominator (LCD) is 10.
Least Common Denominator (LCD) is x2.

3. 5z 1. What is the Least Common Denominator?
2. Change each rational expression into an equivalent
expression with the LCD as the denominator. Leave space to the right of this expression to show what you multiplied by to get the common denominator.

4. 3. Combine the rational expressions over the LCD.
You could also factor the numerator.
Both answers are considered correct.

5. 1. What is the LCD?
10y2
2. Change each rational expression into an equivalent
expression with the LCD as the denominator.
3. Combine the rational expressions.

6. Find the difference.
Both denominators are binomials.
What is the LCD?
Multiply to obtain common denominators.
Simplify each numerator.
Subtract the second numerator from the first.
Can the numerator be factored?
No. The rational expression is in simplest form.

7. Find the difference.
The denominators are inverse binomials. Factor -1 from the denominator on the right.
Subtracting a negative is the same as adding.
The denominators are now the same.
Combine the rational expressions.

8. Find the difference.
The denominators contain inverse binomials. Factor -1 from the denominator on the right.
Subtracting a negative is the same as adding.
What will be the LCD?
Multiply to obtain common denominators.
Remember to leave the rational expression in factored form.

9. Find the sum.
What is the LCD?
Multiply to obtain common denominators.
Simplify each numerator.
Combine.
Can the numerator
be factored?
No.

10. Find the sum.
To determine the LCD, you must first factor the denominator on the left.
Multiply to obtain common denominators.
Simplify each numerator.
Can the numerator be factored?
No. The rational expression is in simplest form.

11. Find the sum.
What will be the LCD?
Multiply to obtain common denominators.
Simplify the numerator.
Can the numerator be factored?

12. Find the difference.
To determine the LCD, you must first factor the denominator on the left.
Multiply to obtain common denominators.
Simplify.
Bring the negative to the front.

13. Adding & Subtracting Rational Expressions with Unlike Denominators
Day 2
White Board Practice
Adding & Subtracting Rational Expressions with Unlike Denominators

14. Find the difference.
Find the sum.

15. Find the difference.

16. Find the difference.

17. Find the sum.

18. Find the sum.

19. Find the difference.

20. A few more…