Answer:
Yes.
Explanation:
Multiply both sides by b to get:
a = bc/d
Then multiply both sides by d to get:
ad = bc
Good? The equality never changed, which means the things on either side of the equals sign always remained equal to each other, because we did the same things to both sides of the equation. That's key: as long as you do that you can move things around at will.
Take care and study hard!