let a,b,c be three integers is a divides c and b divides c, then either a divides b or b divides a.
if a,b,c,d are real numbers with a<b and c<d, then ac<bd.
The Attempt at a Solution
So for part 1
Since a/c and b/c
then, c=ak and c=bd for some integers k,d.
where d/k =l for some integer l.
so a/b=l... Therefore a/b. end of proof.
for part 2)
a<b and c<d (given).
let a= -5 and b=-4 satisfying a<b
and let c=-7 and d=-5 satisfying c<d
so then ac
but this is false
therefore ac<bd is false. end of proof.
Can Someone please tell me if I have done this correctly?