addition and subtraction rational algebraic expressions

addition and subtraction

1. Grade 8 –Mathematics
Quarter I
ADDITION AND SUBTRACTION OF
RATIONAL ALGEBRAIC EXPRESSIONS
(LIKE DENOMINATORS)

2. 1.recalladditionandsubtractionof
similarfractions;and
2.addandsubtractrational
algebraicexpressionswithlike
denominators.

3. How do we add and subtract similar
fractions?
�
�
+
�
�
Similar Fractions
1.Addorsubtractthenumeratorthencopy
thecommondenominator.
2.Simplify,ifpossible.
=
�
�
�
�
-
�
�
=
�
�
=
�
�

4. How do we add and subtract similar
fractions?
�
�
+
�
�
Similar Fractions
1.Addorsubtractthenumeratorthencopy
thecommondenominator.
2.Simplify,ifpossible.
=
�
�
�
�
-
�
�
=
�
�

5. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
1.Add or subtract the numerator.
2.Copy the common denominator.
3.Factor the numerator and cancel out or
divide the common factor then simplify.
�
�
+
�
�
=
�+�
�
�
�
-
�
�
=
�−�
�
�≠�

6. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
��
��
+
�
��
Add the numerator
=
��+�
��
Copy the common
denominator.
Factor the numerator.
Simplify.

7. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
���
��
+
���
��
Add the numerator
=
���
��
Copy the common
denominator.
Factor the numerator.
=
��(��)
��
Simplify.
= ��

8. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
��−�
�
+
��+��
�
Add the numerator
=
��−�+��+��
�Copy the common
denominator.
Factor the numerator.
Simplify.
=
���+�
�=
�(��+�)
�
�
�
=
��+�
�

9. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
��
�
��−�
-
��
��−�
Subtract the numerator =
��
�
−��
��−�
Copy the common
denominator.
Factor.
Simplify.
��
�
−(��)
=
(��+�)(��−�)
��−�
= ��+�

10. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
��
�
�−�
-
�
�
+���
�−�
Subtract the numerator =
��
�
−�
�
−���
�−�
Copy the common
denominator.
Factor.
Simplify.
��
�
−(�
�
+���)
=
8�(�−�)
�−�
= ��
=
��
�
−���
�−�

11. ADDING AND SUBTRACTING RATIONAL
EXPRESSIONS WITH LIKE DENOMINATORS
??????
�
+�??????−��
�??????
�
−�??????
-
�??????+�
�??????
�
−�??????
Subtract the numerator
=
??????
�
+�??????−��−�??????−�
�??????
�
−�??????
Copy the common
denominator.
Factor.
Simplify.
=
??????
�
+�??????−��
�??????
�
−�??????
??????
�
+�??????−��−(�??????+�)
=
(??????+�)(??????−�)
�??????(??????−�)=
??????+�
�??????