what is unit rate???
"When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates."
http://www.eduplace.com/math/mathsteps/6/e/
-14y+12(x+y)-12x
A unit rate is a rate that compares two different quantities in terms of one unit. It is a way to express a ratio between the two quantities in a standardized form. To find the unit rate, you divide the quantity you want to measure by the corresponding unit. Let's consider an example:
Suppose you want to find the unit rate of the number of miles driven in a certain amount of time. If you have driven 240 miles in 4 hours, you divide 240 by 4 to get the unit rate: 240 miles / 4 hours = 60 miles per hour. So, in this case, the unit rate would be 60 miles per hour, indicating that the car is traveling at an average speed of 60 miles per hour.
In summary, a unit rate compares two quantities by dividing one quantity by the corresponding unit to express the ratio in a standardized form.