Posted by **anna** on Friday, January 25, 2013 at 1:29am.

i did use my poof to prove. im not sure im doing right.

here is exercises:

'Suppose a,b,c are integers if a|b and a|c, then a|(b+c).'

my answer:

Proof. Suppose a|b ans a|c.

By Definition of divisibility. we know a|b means there is an integer x with b= ax.

Likewise, a|c means there is an integer y for which c= ay

Thus b+c=(ax+ay)= a(x+y)

therefore a|(b+c).

- elementary math -
**Steve**, Friday, January 25, 2013 at 11:26am
Looks good to me.

- elementary math -
**anna**, Friday, January 25, 2013 at 2:33pm
thank you..

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