Final answer:
To calculate Reese's earnings for babysitting, multiply her hourly rate ($7) by the number of hours worked (x), resulting in the expression 7x.
Step-by-step explanation:
The question asks for an expression that calculates the amount of money Reese makes after babysitting for x hours. To find the total amount of money Reese earns, you would multiply the number of hours she babysits by her rate per hour. Since she charges $7 per hour, the expression to calculate her earnings for x hours of babysitting is 7x, where x represents the number of hours worked.