Answer with explanation:
It is given that, a, b and c belong to the set of integers.
→ gcd(a,c)=d
→GCD=Greatest Common Divisor
→The greatest number which divides both a and c is d.
It means d divides a, and d divides c.
a=d k, for some integer k.-------(1)
c= d m, for some integer m.-------(2)
Now, it is given that, a divides bc.
So,→ 'a' will divide "bdm".--------[using 2, as c=d m]
It shows that, a divides bd, that is a| bd.
Hence proved
