Why only stockholder equity in the well-known accounting equation?

What is the correct formula of accounting equation?

Assets = Liabilities + Equity

Also known as the balance sheet equation, the accounting equation formula is Assets = Liabilities + Equity. This equation should be supported by the information on a company’s balance sheet.

How do you write a statement of stockholders equity?

Quote: Account the statement of stockholders equity is going to tell us what the beginning balance was so we see for example common stock balance at beginning of the year.