Final answer:
The corrected sentence is split into two separate sentences for clarity, indicating John Adams' and George Washington's swearing-in dates correctly.
Step-by-step explanation:
The correct sentence is: Washington's vice president John Adams was sworn in on April 21, 1789. Washington was sworn in as the first president on April 30, 1789. This corrects the original sentence by breaking it into two separate sentences, providing clarity. The first sentence addresses the swearing-in of John Adams, while the second sentence focuses on George Washington's inauguration.
John Adams served as the first Vice President and the second President of the United States. George Washington was unanimously elected as the nation's first president and took his oath of office on the balcony of Federal Hall. The unity and beginnings of the U.S. government were symbolized through these pivotal events in American history.