ALGEBRAIC FRACTIONS
When simplifying algebraic fractions we follow the same
procedure as in arithmetic.
(1) Find LCM of each term in denominators.
(2) Multiply each numerator by the result we get
when the LCM is divided by the denominator
corresponding to the numerator.
(3) Then simplify numerator.
EXAMPLE: EXAMPLE:
2 a - 3 5a + 2
Simplify -
4 6
SOLUTION
2 a - 3 5a + 2
-
4 6
( i ) Find the LCM of 4 and 6 = 12
LCM
( ii ) gives 3, multiply 2a - 3 by 3
4
LCM
( iii ) gives 2, multiply 5a + 2 by 2
6
EXAMPLE: Using the distributive law,
Simplify
7
+
5 3 ( 2 a - 3 ) - 2 ( 5a + 2 )
9 pq 18 p ,
12
SOLUTION we get,
The LCM of 9 pq and 18p is 18pq 6a - 9 - 10a - 4
,
7 5 12
Thus +
9 pq 18 p group like terms then simplify
2 ( 7 ) + q ( 5) 6a - 10a - 9 - 4 -4a - 13
=
18 pq 12 12
14 + 5q
18 pq
EXAMPLE: EXAMPLE:
3 5
Simplify + expressing
Express as a single fraction x-2 x+3
5 p your answer as a single fraction.
-
q 3
SOLUTION
SOLUTION
EXAMPLE:
Express as a single fraction
2m 5m
-
n 3n
SOLUTION
The LCM of n and 3n is 3n
2m 5m
Thus -
n 3n
3 ( 2 m ) - 1 ( 5m )
3n
6m - 5m
3n
m
3n
EXERCISE C7
Express the following as single fractions:
3p q a 3a
+ +
(1) 2 p (2) 5 2
x - 2 x+1 x- 3 x- 2
+ -
(3) 3 4 (4) 3 5
5p +2 3p -1 2k 2 -k
- +
(5) 3 4 (6) 3 5
3 4
+
(7) x x+1 (8)
3 5
+
x - 2 x+3