







Is this operation associative? 
20140114 

patrick pose la question : Associative test: Can you explain the following to me?
Is the following operation associative?: x*y=x+y+1
1) x*(y*z)=x*(y+z+1)=x+(y+z+1)+1=x+y+z+2
2) (x*y)*z=(x+y+1)*z=(x+y+1)+z+1=x+y+z+2
The answer is yes as 1) = 2)
My specific questions are:
1) How x*(y*z)=x*(y+z+1)=x+(y+z+1)+1 ?
2) How (x+y+1)*z=(x+y+1)+z+1?
Thank you!! Penny Nom lui répond. 





An associative binary operation 
20080908 

Skye pose la question : Suppose that * is an associative binary operation on a set S. Show that the set H={a E S such that a*x=x*a for all x E S} is closed under *. (We think of H as consisting of all elements of S that commute with every element in S.)
Thanks! Harley Weston lui répond. 





Is this operation associative? 
20080906 

Francesca pose la question : Determine whether the binary operation * defined is commutative and whether * is associative
* defined on Z by a*b = ab\
I understand how to figure out if it's commutative, but I thought for a binary operation to be associative, it had to have at least three elements, so I don't know how to tell if this associative or not. Penny Nom and Victoria West lui répond. 





Associative or commutative? 
20070824 

Terry pose la question : 5*(7*2)=(7*5)*2 Is this associative property or commutative ??? Both? Penny Nom lui répond. 





A binary operation 
20070731 

sofia pose la question : Prove that if * is associative and commutative binary operation on a set S, then
(a*b)*(c*d) = [(d*c)*a]*b
for all a,b,c,d element in S. Assume the associative Law only for triples as in the definition that is, assume only
(x*y)*z = x*(y*z)
for all x,y,z element in S. Penny Nom lui répond. 





Binary operations 
20070730 

jim pose la question : prove or disprove:
Every binary operation on a set consisting of a single element is both commutative and associative.
Penny Nom lui répond. 





Fill in the blanks 
20061004 

Justin pose la question : 1. To find out about how much, you can
2. The  states that the sum is the same no matter who you group the addends. Stephen La Rocque lui répond. 





Addends can be grouped differently but the sum does not change 
20020903 

Jodia pose la question : I have been searching the web for over an hour & a half now for the answer to the following question: The _____ states that addends can be grouped differently but the sum does not change. Penny Nom lui répond. 





Definitions 
19970908 

SohoGirl13 pose la question : I am an 8th grader. my email address is SohoGirl13@aol.com. I have a question: what are the associative, communitive, and distributive properties? Harley Weston lui répond. 

