The last one is the answer
        
             
        
        
        
Answer:
- Option <u>B </u>is correct i.e. <u>2</u><u>1</u>
Step-by-step explanation:
In the question we're provided with an equation that is :
And we are asked to find the solution for the equation .
<u>Solution</u><u> </u><u>:</u><u> </u><u>-</u>
<u> </u>
</u>
Multiplying by 7 on both sides :

On further calculations , we get : 

- <u>Therefore</u><u> </u><u>,</u><u> </u><u>solution</u><u> </u><u>for</u><u> equation</u><u> </u><u>is </u><u>2</u><u>1</u><u> </u><u>.</u><u>That </u><u>means</u><u> </u><u>option </u><u>B </u><u>is </u><u>the </u><u>correct</u><u> answer</u><u>.</u>
<u>Verifying</u><u> </u><u>:</u>
We are verifying our answer by substituting value of v in the equation given in question :

Putting value of v :

By dividing 21 with 7 , we get :



- <u>Therefore</u><u> </u><u>,</u><u> </u><u>our </u><u>answer</u><u> is</u><u> valid</u><u> </u><u>.</u>
<h2>
<u>#</u><u>K</u><u>e</u><u>e</u><u>p</u><u> </u><u>Learning</u></h2>
 
        
                    
             
        
        
        
It's "commutative property," which says that (for addition/multiplication) order of the operator doesn't matter. For eg, 3 * 5 = 5 * 3. 
Associative property (again, of multiplication and addition) means that it doesn't matter how you solve an expression if the same operand is used and some numbers are grouped. For eg. 3 * (5 * 4) = (3 * 5) * 4.
        
             
        
        
        
If your question is how many positions are possible, then the answer is 24.
We find this by thinking of how many people can be in each spot. If there are 4 spots each person can stand (back left, back right, front left, front right), then there are 4 possible choice for the first spot (mom, dad, son, daughter), then 3 for the next spot (since 1 is already in a spot), then 2 options for the next spot, and then 1 option for the last spot. In other words, the answer is 4x3x2x1, or 4 factorial.