<< Chapter < Page Chapter >> Page >

The number 50 is between what two whole numbers?

Since 7 2 = 49 , 49 = 7.

Since 8 2 = 64 , 64 = 8. Thus,

7 < 50 < 8

Thus, 50 is a number between 7 and 8.

A number line with arrows on each end, labeled at zero, seven and eight. Seven is also labeled as square root of forty-nine and eight is labeled as square root of sixty-four. There is a closed circle at square root of fifty and it is labeled as square root of fifty.

Got questions? Get instant answers now!

Practice set b

Write the principal and secondary square roots of each number.

100

100 = 10 and 100 = 10

Got questions? Get instant answers now!

121

121 = 11 and 121 = 11

Got questions? Get instant answers now!

Use a calculator to obtain a decimal approximation for the two square roots of 35. Round to two decimal places.

5.92  and  5.92

Got questions? Get instant answers now!

Meaningful expressions

Since we know that the square of any real number is a positive number or zero, we can see that expressions such as 16 do not describe real numbers. There is no real number that can be squared that will produce −16. For x to be a real number, we must have x 0. In our study of algebra, we will assume that all variables and all expressions in radicands represent nonnegative numbers (numbers greater than or equal to zero).

Sample set c

Write the proper restrictions that must be placed on the variable so that each expression represents a real number.

For x 3 to be a real number, we must have

x 3 0 or x 3

Got questions? Get instant answers now!

For 2 m + 7 to be a real number, we must have

2 m + 7 0 or 2 m 7 or m 7 2

Got questions? Get instant answers now!

Practice set c

Write the proper restrictions that must be placed on the variable so that each expression represents a real number.

Simplifying square roots

When variables occur in the radicand, we can often simplify the expression by removing the radical sign. We can do so by keeping in mind that the radicand is the square of some other expression. We can simplify a radical by seeking an expression whose square is the radicand. The following observations will help us find the square root of a variable quantity.

Since ( x 3 ) 2 = x 3 · 2 = x 6 , x 3 is a square root of x 6 . Also
Six divided by two is equal to three. There is an arrow pointing  towards six that is labeled as

Got questions? Get instant answers now!

Since ( x 4 ) 2 = x 4 · 2 = x 8 , x 4 is a square root of x 8 . Also

Eight divided by two is equal to four. There is an arrow pointing  towards eight that is labeled as

Got questions? Get instant answers now!

Since ( x 6 ) 2 = x 6 · 2 = x 12 , x 6 is a square root of x 12 . Also

Twelve divided by two is equal to six. There is an arrow pointing  towards twelve that is labeled as

Got questions? Get instant answers now!

These examples suggest the following rule:

If a variable has an even exponent, its square root can be found by dividing that exponent by 2.

The examples of Sample Set B illustrate the use of this rule.

Sample set d

Simplify each expression by removing the radical sign. Assume each variable is nonnegative .

a 2 . We seek an expression whose square is  a 2 .  Since ( a ) 2 = a 2 , a 2 = a Notice that  2 ÷ 2 = 1.

Got questions? Get instant answers now!

y 8 . We seek an expression whose square is  y 8 .  Since ( y 4 ) 2 = y 8 , y 8 = y 4 Notice that  8 ÷ 2 = 4.

Got questions? Get instant answers now!

25 m 2 n 6 . We seek an expression whose square is  25 m 2 n 6 .  Since ( 5 m n 3 ) 2 = 25 m 2 n 6 , 25 m 2 n 6 = 5 m n 3 Notice that  2 ÷ 2 = 1  and  6 ÷ 2 = 3.

Got questions? Get instant answers now!

121 a 10 ( b 1 ) 4 . We seek an expression whose square is  121 a 10 ( b 1 ) 4 . Since [ 11 a 5 ( b 1 ) 2 ] 2 = 121 a 10 ( b 1 ) 4 , 121 a 10 ( b 1 ) 4 = 11 a 5 ( b 1 ) 2 Then, 121 a 10 ( b 1 ) 4 = 11 a 5 ( b 1 ) 2 Notice that  10 ÷ 2 = 5  and  4 ÷ 2 = 2.

Got questions? Get instant answers now!

Practice set d

Simplify each expression by removing the radical sign. Assume each variable is nonnegative.

100 x 8 y 12 z 2

10 x 4 y 6 z

Got questions? Get instant answers now!

36 ( a + 5 ) 4

6 ( a + 5 ) 2

Got questions? Get instant answers now!

225 w 4 ( z 2 1 ) 2

15 w 2 ( z 2 1 )

Got questions? Get instant answers now!

0.25 y 6 z 14

0.5 y 3 z 7

Got questions? Get instant answers now!

x 2 n , where n is a natural number.

x n

Got questions? Get instant answers now!

x 4 n , where n is a natural number.

x 2 n

Got questions? Get instant answers now!

Exercises

How many square roots does every positive real number have?

two

Got questions? Get instant answers now!

The symbol represents which square root of a number?

Got questions? Get instant answers now!

The symbol – represents which square root of a number?

secondary

Got questions? Get instant answers now!

For the following problems, find the two square roots of the given number.

1 16

1 4 and 1 4

Got questions? Get instant answers now!

25 36

5 6  and  5 6

Got questions? Get instant answers now!

0.04

0.2 and 0.2

Got questions? Get instant answers now!

1.21

1.1 and 1.1

Got questions? Get instant answers now!

For the following problems, evaluate each expression. If the expression does not represent a real number, write "not a real number."

225

not a real number

Got questions? Get instant answers now!

1

not a real number

Got questions? Get instant answers now!

For the following problems, write the proper restrictions that must be placed on the variable so that the expression represents a real number.

2 x 8

x 4

Got questions? Get instant answers now!

For the following problems, simplify each expression by removing the radical sign.

36 x 22 y 44

6 x 11 y 22

Got questions? Get instant answers now!

169 w 4 z 6 ( m 1 ) 2

Got questions? Get instant answers now!

25 x 12 ( y 1 ) 4

5 x 6 ( y 1 ) 2

Got questions? Get instant answers now!

9 m 6 n 4 ( m + n ) 18

3 m 3 n 2 ( m + n ) 9

Got questions? Get instant answers now!

( f 2 ) 2 ( g + 6 ) 4

( f 2 ) ( g + 6 ) 4

Got questions? Get instant answers now!

( 2 c 3 ) 6 + ( 5 c + 1 ) 2

Got questions? Get instant answers now!

64 r 4 s 22

8 r 2 s 11

Got questions? Get instant answers now!

121 a 6 ( a 4 ) 8

Got questions? Get instant answers now!

[ ( w + 6 ) 2 ]

w + 6

Got questions? Get instant answers now!

[ 4 a 2 b 2 ( c 2 + 8 ) 2 ]

Got questions? Get instant answers now!

1.21 h 4 k 4

1.1 h 2 k 2

Got questions? Get instant answers now!

169 a 2 b 4 c 6 196 x 4 y 6 z 8

13 a b 2 c 3 14 x 2 y 3 z 4

Got questions? Get instant answers now!

[ 81 y 4 ( z 1 ) 2 225 x 8 z 4 w 6 ]

Got questions? Get instant answers now!

Exercised for review

( [link] ) Find the quotient. x 2 1 4 x 2 1 ÷ x 1 2 x + 1 .

x + 1 2 x 1

Got questions? Get instant answers now!

( [link] ) Find the sum. 1 x + 1 + 3 x + 1 + 2 x 2 1 .

Got questions? Get instant answers now!

( [link] ) Solve the equation, if possible: 1 x 2 = 3 x 2 x 2 3 x + 1 .

No solution ; x = 2 is excluded.

Got questions? Get instant answers now!

( [link] ) Perform the division: 15 x 3 5 x 2 + 10 x 5 x .

Got questions? Get instant answers now!

( [link] ) Perform the division: x 3 5 x 2 + 13 x 21 x 3 .

x 2 2 x + 7

Got questions? Get instant answers now!

Questions & Answers

how do you get the 2/50
Abba Reply
number of sport play by 50 student construct discrete data
Aminu Reply
width of the frangebany leaves on how to write a introduction
Theresa Reply
Solve the mean of variance
Veronica Reply
Step 1: Find the mean. To find the mean, add up all the scores, then divide them by the number of scores. ... Step 2: Find each score's deviation from the mean. ... Step 3: Square each deviation from the mean. ... Step 4: Find the sum of squares. ... Step 5: Divide the sum of squares by n – 1 or N.
kenneth
what is error
Yakuba Reply
Is mistake done to something
Vutshila
Hy
anas
hy
What is the life teble
anas
hy
Jibrin
statistics is the analyzing of data
Tajudeen Reply
what is statics?
Zelalem Reply
how do you calculate mean
Gloria Reply
diveving the sum if all values
Shaynaynay
let A1,A2 and A3 events be independent,show that (A1)^c, (A2)^c and (A3)^c are independent?
Fisaye Reply
what is statistics
Akhisani Reply
data collected all over the world
Shaynaynay
construct a less than and more than table
Imad Reply
The sample of 16 students is taken. The average age in the sample was 22 years with astandard deviation of 6 years. Construct a 95% confidence interval for the age of the population.
Aschalew Reply
Bhartdarshan' is an internet-based travel agency wherein customer can see videos of the cities they plant to visit. The number of hits daily is a normally distributed random variable with a mean of 10,000 and a standard deviation of 2,400 a. what is the probability of getting more than 12,000 hits? b. what is the probability of getting fewer than 9,000 hits?
Akshay Reply
Bhartdarshan'is an internet-based travel agency wherein customer can see videos of the cities they plan to visit. The number of hits daily is a normally distributed random variable with a mean of 10,000 and a standard deviation of 2,400. a. What is the probability of getting more than 12,000 hits
Akshay
1
Bright
Sorry i want to learn more about this question
Bright
Someone help
Bright
a= 0.20233 b=0.3384
Sufiyan
a
Shaynaynay
How do I interpret level of significance?
Mohd Reply
It depends on your business problem or in Machine Learning you could use ROC- AUC cruve to decide the threshold value
Shivam
how skewness and kurtosis are used in statistics
Owen Reply
yes what is it
Taneeya
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Elementary algebra' conversation and receive update notifications?

Ask