Do you mean xy instead of sy if so i’m pretty sure you would just multiply both of the numbers
Consider,

. Let's say

then the problem reduces to

. (Do you understand this step?)
So then replacing a again with our definition we get,

.
Answers:
1. There are rivets on the belts.
2. Extra information given in the problem:
a. He has 9 buckles.
b. He has 22 rivets left over.
Solution:
1. Total rivets on the belts=(12 rivets/belt)(4 belts)+(15 rivets/belt)(2 belts)
Total rivets on the belts=48 rivets+30 rivets
Total rivets on the belts=78 rivets
2. The extra information given in the problem is the information that we didn't use to solve it. In this case:
a. He has 9 buckles.
b. He has 22 rivets left over.
Is there a picture to find the answer?
The average speed can be obtained by the formula:

If a boat travels 36 miles in 1.5 hours ans then in 14 miles in 0.75 hour, then find:
- total distance is 36+14=50 miles;
- total time: 1.5+0.75=2.25 hours.
Therefore,
miles per hour.
Answer:
miles per hour.