Simplifying Radical Expressions

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Simplifying Radical

Expressions

Product Property of

Radicals

For any numbers a and b where a

0 and b

0 ,

ab

 a

 b

Product Property of

Radicals Examples

72 36

2

36

6 2

2

48

16

3

16

4 3

3

Examples:

1. 30 a

34  a

34

 a

17

30

30

2. 54 x

4 y

5 z

7 

9 x

4 y

4 z

6

3 x

2 y

2 z

3

6 yz

6 yz

Examples:

3

3. 54 a

3 b

7  3

27 a

3 b

7  3

2 b

3 ab

2  3

2 b

4. 60 xy

3 

4 y

2 

15 xy

2 y 15 xy

Quotient Property of

Radicals

For any numbers a and b where a

0 and b

0 , a b

 a b

Examples:

1.

7

16

7

16 4

7

2.

32

25

32

25

32

5

4 2

5

Examples:

3.

48

3

48

16

4

3

4.

45

4

45

4

45

2

3 5

2

Rationalizing the denominator

Rationalizing the denominator means to remove any radicals from the denominator.

Ex: Simplify

5

3

5

3

3

3

5 3

9

5 3

3

15

3

Simplest Radical Form

•No perfect nth power factors other than 1.

•No fractions in the radicand.

•No radicals in the denominator.

Examples:

1.

5

4

5

4 2

5

2.

20 8

2 2

10

8

2

10 4

10

2

20

Examples:

3.

5

2 2

2

2

5 2

2 4

5 2

2

2

5 2

4

4. 4

5

7x

4 5

7 x

7 x

7 x

4 35

49 x 2 x

4 35 x

7 x

Adding radicals

We can only combine terms with radicals if we have like radicals

6 7

5 7

3 7

6

5

3

7

8 7

Reverse of the Distributive Property

Examples:

1. 2 3 + 5 + 7 3 - 2

= 2 3 + 7 3 + 5 - 2

= 9 3 + 3

Examples:

2. 5 6

3 24

150

= 5 6

3 4 6

25 6

= 5 6

6 6

5 6

= 4 6

Multiplying radicals -

Distributive Property

3

2

4 3

3

2

3

4 3

6

12

Multiplying radicals - FOIL

3

5

F

 

2

O

4 3

3

2

3

4 3

I

L

5

2

5

4 3

6

12

10

4 15

1. 2 3

Examples:

4 5

 

3

6 5

F O

2 3

3

2 3

6 5

I

L

4 5

3

4 5

6 5

6

12 15

4 15

120

16 15

126

Examples:

F

2

2 7

5 4

2 7

5

O

10

10

10

2 7

2

2 7

2 7

I L

2 7

10

2 7

2 7

100

20 7

20 7

4 49

100

4

7

72

Conjugates

Binomials of the form

a b

 c d and a b

 c d where a, b, c, d are rational numbers.

Ex : 5

6

Conjugate: 5

6

3

2 2

Conjugate: 3

2 2

What is conjugate of 2 7

3?

Answer : 2 7

3

The product of conjugates is a rational number. Therefore, we can rationalize denominator of a fraction by multiplying by its conjugate.

Examples:

1.

3

2

3

5

3

5

3

5

3

3

5

3

2 3

2

5

 

2

5 2

3

7 3

10

3

25

13

7 3

22

Examples:

2.

1

2 5

6

5

6

5

6

5

6

5

12 5

10

6 2 

 

2

16

13 5

31

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