Algebra Demystified 2nd Ed

18 alGebra De mystif ieD

EXAMPLE

Find the sum or difference after computing the LCD.

17

24

5

36

+

SOLUTION

24 = 2 ⋅ 2 ⋅ 2 ⋅ 3 and 36 = 2 ⋅ 2 ⋅ 3 ⋅ 3

The LCD = 2 ⋅ 2 ⋅ 2 ⋅ 3 ⋅ 3 = 72; 72 ÷ 24 = 3; and 72 ÷ 36 = 2. We multiply^1724 by

(^33) and 365 by (^22).
17
24
5
36
17
24
3
3
5
36
2
2
51
72
10
72
+= ⋅^6



+⋅



=+=^11
72
PRACTICE
Find the sum or difference after computing the LCD.

1.^11
12

5

18

−=

2.^7
15

9

20

+=

3.^23
24

7

16

+=

4.^3
8

7

20

+=

5.^1
6

4

15

+=

6.^8
75

3

10

+=

7.^35
54

7

48

−=

8.^15
88

3

28

+=

9.^119
180

17

210

+=

EXAMPLE

Find the sum or difference after computing the LCD.

PRACTICE

Find the sum or difference after computing the LCD.

✔SOLUTION