Question

Show that if a, b, c and d are integers, where! = 0, such that a | c and b | d, then ab | cd?

Answer 1

@ganeshie8

Answer 2

@SolomonZelman

Answer 3

a|c implies c=ax,where x is an integer.
b|d implies d=by,where y is an integer
ab|cd iff ab|axby
iff ab|abxy
which is true.
Hence ab|cd