Hello there! An example problem for this could be:
Emile is looking for a cell-phone plan. His two options are one that costs $40 up front, and costs $0.01 per text, represented by x. The second one is 15 dollars up front and costs $0.06 for each text message. Emile figures that for the first package he has to send 500 texts or more to make it less than the second one.
Answer:
Step-by-step explanation:
Let x be the number of flowers. If Group A were to make x flowers alone, it would take them 10 hours to complete the task, then they make 
flowers in an hour. If Group B were to make x flowers alone, it would take them 15 hours to complete the task, then they make 
flowers in an hour.
The groups decided to work together. They can make 
together in an hour and it takes them 
hours. Group B took a break for 1 hour and 40 minutes (
hour), then Group B works
hours.
Thus,
10*12=120+29=149 hoped i helped
You can combine the same numbers with the same variables using the operation sign for each. For example, using your equation, you would combine the 3n and 4n which is 7n. So your equation would be
7n - 2
All of it is 8 because sides are all equal
