What are those mysterious square roots that often confuse students and complicate their lives? The truth is that to understand them, we need to grasp the concept of the inverse operation.

What is a square root?

When we solve an exercise like 5=252 5=25^2 , it's clear that 5 5 times 5 5 (that is, multiplying the number by itself) results in 25 25 . This is the concept of a power, or to be more precise, a square power, which to apply, we must multiply the figure or the number by itself.

The concept of "square root" refers to the inverse operation of squaring numbers.

That is, if we have X2=25X^2=25 and we want to find the value of XX, what we need to do is perform an identical operation on both sides of the equation.

A - The concept of square root refers to the inverse operation of squaring numbers

This operation is the square root.

So, we have: X2=25\sqrt{X^2} = \sqrt{25} and the result is X=5 X=5 .

Suggested Topics to Practice in Advance

  1. Exponents and Roots - Basic
  2. Exponents and Exponent rules
  3. Basis of a power
  4. The exponent of a power
  5. Powers

Practice Square Roots

Examples with solutions for Square Roots

Exercise #1

Choose the largest value

Video Solution

Step-by-Step Solution

Let's begin by calculating the numerical value of each of the roots in the given options:

25=516=49=3 \sqrt{25}=5\\ \sqrt{16}=4\\ \sqrt{9}=3\\ We can determine that:

5>4>3>1 Therefore, the correct answer is option A

Answer

25 \sqrt{25}

Exercise #2

Solve the following exercise:

x2= \sqrt{x^2}=

Video Solution

Step-by-Step Solution

In order to simplify the given expression, we will use two laws of exponents:

a. The definition of root as an exponent:

an=a1n \sqrt[n]{a}=a^{\frac{1}{n}} b. The law of exponents for power of a power:

(am)n=amn (a^m)^n=a^{m\cdot n}

Let's start with converting the square root to an exponent using the law mentioned in a':

x2=(x2)12= \sqrt{x^2}= \\ \downarrow\\ (x^2)^{\frac{1}{2}}= We'll continue using the law of exponents mentioned in b' and perform the exponent operation on the term in parentheses:

(x2)12=x212x1=x (x^2)^{\frac{1}{2}}= \\ x^{2\cdot\frac{1}{2}}\\ x^1=\\ \boxed{x} Therefore, the correct answer is answer a'.

Answer

x x

Exercise #3

441= \sqrt{441}=

Video Solution

Step-by-Step Solution

The root of 441 is 21.

21×21= 21\times21=

21×20+21= 21\times20+21=

420+21=441 420+21=441

Answer

21 21

Exercise #4

5+361= 5+\sqrt{36}-1=

Video Solution

Step-by-Step Solution

To solve the expression 5+361= 5+\sqrt{36}-1= , we need to follow the order of operations, often remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).


Here are the steps:


First, calculate the square root:

36=6 \sqrt{36} = 6

Substitute the square root back into the expression:

5+61 5 + 6 - 1

Next, perform the addition and subtraction from left to right:

Add 5 and 6:

5+6=11 5 + 6 = 11

Then subtract 1:

111=10 11 - 1 = 10

Finally, you obtain the solution:

10 10

Answer

10 10

Exercise #5

81+81+10= 81+\sqrt{81}+10=

Video Solution

Step-by-Step Solution

To solve the expression 81+81+10 81+\sqrt{81}+10 , we need to follow the order of operations, often abbreviated as PEMDAS (Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right)).

Here, the expression contains a square root, which is a type of exponent operation. Therefore, we will handle the square root first:

  • Find the square root of 81, which is calculated as follows: 81=9 \sqrt{81} = 9 .

Now substitute the result back into the original expression:

81+9+10 81 + 9 + 10

Next, perform the addition operations from left to right:

  • First, add 81 and 9: 81+9=90 81 + 9 = 90 .
  • Then, add the result to 10: 90+10=100 90 + 10 = 100 .

Therefore, the final result of the expression 81+81+10 81+\sqrt{81}+10 is:

100 100

Answer

100 100

Exercise #6

143121+18= 143-\sqrt{121}+18=

Video Solution

Step-by-Step Solution

To solve the expression 143121+18 143-\sqrt{121}+18 , we need to follow the order of operations, which dictate that we should simplify any expressions under a square root first, followed by subtraction and addition.


Step 1: Simplify the square root:

  • Calculate the square root: 121 \sqrt{121} .
  • The square root of 121 is 11, because 11×11=121 11 \times 11 = 121 .

Now, substitute back into the expression:

  • The expression becomes: 14311+18 143 - 11 + 18 .

Step 2: Perform the subtraction:

  • Calculate 14311 143 - 11 .
  • This equals 132, because subtracting 11 from 143 yields 132.

Step 3: Perform the addition:

  • Now add 18 to the result of the subtraction: 132+18 132 + 18 .
  • The result is 150, because adding 18 to 132 equals 150.

Therefore, the final answer is 150 150 .

Answer

150 150

Exercise #7

(380.2512)211= (\sqrt{380.25}-\frac{1}{2})^2-11=

Video Solution

Step-by-Step Solution

According to the order of operations, we should first solve the expression inside of the parentheses:

(380.2512)=(19.512)=(19) (\sqrt{380.25}-\frac{1}{2})=(19.5-\frac{1}{2})=(19)

In the next step, we will proceed to solve the exponentiation, and finally the subtraction:

(19)211=(19×19)11=36111=350 (19)^2-11=(19\times19)-11=361-11=350

Answer

350

Exercise #8

4×0.49+42= 4\times\sqrt{0.49}+4^2=

Video Solution

Step-by-Step Solution

To solve the expression 4×0.49+42= 4\times\sqrt{0.49}+4^2 = , we will follow the order of operations, which prioritizes operations inside parentheses, exponents and roots, followed by multiplication and division, and finally addition and subtraction.

1. Calculate the Square Root:
The first step is to solve the square root part of the expression. 0.49 \sqrt{0.49} .
0.49 0.49 is a simple decimal number whose square root is 0.7 0.7 , because 0.7×0.7=0.49 0.7 \times 0.7 = 0.49 .
So,0.49=0.7 \sqrt{0.49} = 0.7 .

2. Multiply:
Next, we multiply the result of the square root by 4:
4×0.7=2.8 4 \times 0.7 = 2.8 .

3. Calculate the Power:
Evaluate 42 4^2 .
42=16 4^2 = 16 , because 4×4=16 4 \times 4 = 16 .

4. Addition:
Now, add the results from the previous steps:
2.8+16=18.8 2.8 + 16 = 18.8 .

The final result of the expression 4×0.49+42 4\times\sqrt{0.49}+4^2 is 18.8 \boxed{18.8} .

Answer

18.8

Exercise #9

49= \sqrt{49}=

Video Solution

Answer

7

Exercise #10

36= \sqrt{36}=

Video Solution

Answer

6

Exercise #11

64= \sqrt{64}=

Video Solution

Answer

8

Exercise #12

x=1 \sqrt{x}=1

X=? X=?

Video Solution

Answer

1

Exercise #13

x=2 \sqrt{x}=2

Video Solution

Answer

4

Exercise #14

x=6 \sqrt{x}=6

Video Solution

Answer

36

Exercise #15

4= \sqrt{4}=

Video Solution

Answer

2

Topics learned in later sections

  1. Square Root of a Negative Number