Multlipication And Division of Algebraic Fractions JSS2 Mathematics Lesson Note

 ALGERAIC FRACTIONS 

To add or subtract fractions with different denominators, first change them to equivalent fractions. This is done by finding the L C M of the denominators

Example1: Simplify 2a/5 + 4a/3

Solution:

The L C M is 15

6a + 20a/ 15 = 26a/15

Example 2: Simplify 3/5x + 1/2x – 1/4x

Solution:

Find the L C M of the expression = 20X

12 + 10 – 5 = 17/20X

SIMPLIFYING FRACTION 

Example 1: Reduce 25X4Y3/35X3y3

solution

Divide through by 5X3Y3(the common factor )

= 5x/7

Example 2: Reduce 8X3Y2/6X3Z

Solution:

Divide through by 2X 3(the common factor)

4Y2/3Z

MULTIPLICATION AND DIVISION OF ALGEBRAIC FRACTION 

Example 1: Simplify (X-2)/7 * 4/(X-2)

Solution : X – 2/7 * 4/ X -2 (X-2) divides themselves

= 4/7

Example 2: Simplify 6X2/11y ÷ 18X/33Y2

Solution

6X2/11y * 33Y2/18X (division sign change to multiplication)

= XY

FRACTIONS WITH BRACKETS

Example1: simplify the following (a) 2x + 5/4 + 2X – 3 /4 (b) 7X – 2 /4 + X – 4 /6

Solution:

(a).  The L C M is 4

(2X + 5) + ( 2X – 3)/4

4x + 2/4 = 2(2X + 1)/4

= 2X + 1/2

(b).  7X – 2 /4 + X – 4 /6

Solution:

The L C M = 12

21x – 6 + 2X – 6 – 8 / 12

= 23X – 14/ 12