First, let's figure how much will 12% discount take off 10,000 dollars worth of goods. 
To do that, we can multiply 12 by 10,000 and then divide by 100 to get the discount. 
12 x 10,000 = 120,000
120,000/100 = 1,200 
The discount for 12% of 10,000 is 1,200 dollars off. 
Then, we would subtract that from 10,000. 
10,000 - 1,200 = 8,800 
After that, we need to solve for the amount taken off 17% of 8,800. 
Same thing, multiply 17 by 8,800 and then divide by 100.
17 x 8,800 = 149600
149,600/100 = 1496 
Lastly subtract that from 8800. 
8800 - 1496 = 7304 
Therefore, the final cost of $18,000 worth of appliances is $7,304 plus tax.