Answer:
x = 4.5 
Explanation:
Let's begin by writing the equation in words to express the worker's earnings: 
 Rate x Time = Earnings 
 
Now let's rewrite this equation replacing the words with our given numerical facts and our unknown (x): 
 
 Rate x Time = Earnings 
 
 Rate = $7.50 per hour 
 Time = x (# hours worked) 
 Earnings = 33.75 
 
 (7.50)(x) = 33.75 
 
Finally, we'll solve our equation for our unknown (x): 
 (7.50)(x) = 33.75 
 7.50x = 33.75 
 x = 33.75/7.50 
 x = 4.5 (# hours worked)