John’s bank is overdrawn. After he makes a $120 deposit, John sees that his account still is overdrawn by $75. So what was John's balance before making his deposit?

Translate the words into an equation.
Let B represent the original balance.
Original Balance+ John Deposit=Current Balance
B + $120 = −$75
To isolate un unknown value B, subtract 120 from both sides.
B+120-120=-75-120
Simplify both sides.
B=-195
The original balance was overdrawn to the tune of $195.