#### Explanation:

Let's first set up an equation and identify the variables.

We are given that $7 is earned every hour worked. We can represent this mathematically as: $7 x$, where $x$represents the number of hours. If we were to say this aloud, we would be saying "seven dollars per hour". $7 x$To make this an equation that can be solvable, we need to set this term equal to something, and we can use another variable. $y = 7 x$We are told that $120$hours were worked. We can plug this into $x$, since $x$represents hours. $y = 7 \left(120\right)$Now we need to simplify. Multiply $7$and $120$. $y = 840$We found out that $840 was earned when $7 was made every hour, for $120\$ hours.