Answer:
The significance of Marbury v. Madison was that it was the first U.S. Supreme Court case to apply "Judicial Review", and it allowed the Supreme Court to rule laws unconstitutional.
Marbury v. Madison strengthened the federal judiciary by establishing for it the power of judicial review, by which the federal courts could declare legislation, as well as executive and administrative actions, inconsistent with the U.S. Constitution (“unconstitutional”) and therefore null and void.
There you go hope that helps!!!