Algebra Demystified 2nd Ed

Chapter 2 IntroduCtIon to VarIables 55

deMYstiFied / algebra deMYstiFied / HuttenMuller / 000-0 / Chapter 2

LCD = 2⋅ 2 ⋅ 3 ⋅ 5 ⋅ 7 ⋅x = 420x and 420x ÷ 84 = 5x and 420x ÷ 30 x = 14

420

84

5 420

30

x x x 14

x

 ==







and

71

84

13

30

−

x

=⋅^71 −⋅=−=−

84

5

5

13

30

14

14

355

420

182

420

x 355 182

xx

x

xx

x

4420 x

PRACTICE

Find the sum. Do not try to simplify the solutions. We will learn how to

simplify this type of fraction in a later chapter.

1.^4
15

2

33

+=x

2. x
   48

7

30

−=

3.^34
x 25

+=

4.^2
45

6

x 35

+=

5.^11
150

7

x 36

+=

6.^2
21

3

xx 98

+=

7.^1
21

5

xy 9

+=

8.^19
51

1

yx 6

−=

9.^7
24

2

15

x

yy

+=

10.^3
14

2

yx 35

+=

SOLUTIONS

1.^4
15

2

33

4

15

11

11

2

33

5

5

44

165

10

165

44 10

16

+=xx⋅+ ⋅= +=xx+

55

2. xx xx
   48

7

30 48

5

5

7

30

8

8

5

240

56

240

556

240

−=⋅−⋅=−=−

PRACTICE

Find the sum. Do not try to simplify the solutions. We will learn how to

✔SOLUTIONS