What is a simplified expression for (x−y)−(x+y)?

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

If a sprinkler waters 1 over 12 of a lawn in 1 over 2 hour, how much time will it take to water the entire lawn? (5 points) 10 hours 6 hours 1 over 6 hour 7 over 12 hour

Henry's butcher shop uses an electronic scale that measures to 1/100 of a pound. which is the most accurate measurement based on the limitations of the scale that might be found on a package of meat sold by henry?