Answer: Each pen cost $3.12
Step-by-step explanation:
If you divide 31.20 by 10 you will get 3.12. Each pen costs the same amount so that amount ten times would equal $31.20. To find out how much one pen costs you need solve for only one out of these ten pens which is why you divide.
For this case we have the following inequations:
1.5x-1> 6.5
7x + 3 <-25
Clearing x from each one we have:
For 1.5x-1> 6.5:
1.5x> 6.5 + 1
1.5x> 7.5
x> 7.5 / 1.5
x> 5
For 7x + 3 <-25:
7x <-25-3
7x <-28
x <-28/7
x <-4
The solution set is:
(inf, -4) U (5, inf)
Answer:
See attached image