Mandy Anabelle decided to open Mandy's Nail Spa. Mandy completed the following transactions:
a. Invested $21,000 cash from her personal bank account into the business.
b. Bought store equipment for cash, $3,500.
c. Bought additional store equipment on account, $5,750.
d. Paid $1,000 cash to partially reduce what was owed from transaction C.
Based on this information, record these transactions into the basic accounting equation.