Hi

I need help with the following question

I have attached my question.

I haven't got a clue on how to start the question.

thanks

Printable View

- December 26th 2009, 11:42 AMcooltownsquestion involving modulus (congrency)
Hi

I need help with the following question

I have attached my question.

I haven't got a clue on how to start the question.

thanks - December 26th 2009, 11:47 AMtonio
- December 26th 2009, 11:50 AMcooltowns
can you please show me how to do it, i would appreichate this. I have a few questions which are similar to this. So if i have fully worked out solution to one i can try others on my own.

thanks - December 26th 2009, 05:10 PMHallsofIvy
You solve it by

**doing**it! What is ? What is ? What is ? What is ? What is ? What is ? What is What is ?

Now reduce "(mod 7)". Since 7= 0 (mod 7) that reduces to (mod 7). Is there any integer y for which that is true? Replace with 0, 1, 2, and 4 to see. - December 27th 2009, 12:39 AMcooltowns
could you please explain how the

i don't understand where the 2 came from and why you have chosen mod7 in particular.

thanks - December 27th 2009, 01:26 AMCaptainBlack
Obviously:

Now we know that

So what are the possible values of and are any of these congruent to

CB - December 27th 2009, 01:56 AMcooltowns
but why 2(mod7). As i understand the mod 7 comes from the equation but could you please explain where the 2 came from ?

thank you - December 27th 2009, 02:26 AMCaptainBlack
It's the right hand side of your d**n problem:

There is a bit of a hint also in the question that is involved.

To prove that an equation has no integer solutions it is sufficient to show that it has no solution modulo some integer.

(As a hint in future read your own problem when you post it)

CB - December 27th 2009, 04:19 AMcooltowns
thanks for all the replies.

(Wink)