#### Answer

Estimate: 4000; Exact: 3583

#### Work Step by Step

To estimate, first we round 2633 to 3000, 90 to 100, and 230 to 200. We find the estimated total cost by adding the estimated cost of the new transaxle, the total cost of labor (hours x cost per hour), and the estimated sales tax: 3000 + 8*100 + 200 = 3000 + 800 + 200 = 4000.
To find the exact cost, we add the actual cost of the new transaxle, the total cost of labor (hours x cost per hour), and the actual sales tax: 2633 + 8*90 + 230 = 3583