Answers 1 and 3 are functions.
Answer: 480 cubes touch the box
Step-by-step explanation:
Answer:
![(a)\ 4 < 5x - 1 < 10](https://tex.z-dn.net/?f=%28a%29%5C%204%20%3C%205x%20-%201%20%3C%2010)
![(b)\ 4 < 5x - 3 < 10](https://tex.z-dn.net/?f=%28b%29%5C%204%20%3C%205x%20-%203%20%3C%2010)
![(d)\ 4 < 2x + 1 < 10](https://tex.z-dn.net/?f=%28d%29%5C%204%20%3C%202x%20%2B%201%20%3C%2010)
![(e)\ 4 < 2x + 3 < 10](https://tex.z-dn.net/?f=%28e%29%5C%204%20%3C%202x%20%2B%203%20%3C%2010)
Step-by-step explanation:
Required
Whose solution is ![x = 2](https://tex.z-dn.net/?f=x%20%3D%202)
![(a)\ 4 < 5x - 1 < 10](https://tex.z-dn.net/?f=%28a%29%5C%204%20%3C%205x%20-%201%20%3C%2010)
Add 1 to both parts
![4 +1< 5x < 10+1](https://tex.z-dn.net/?f=4%20%2B1%3C%205x%20%20%3C%2010%2B1)
![5< 5x < 11](https://tex.z-dn.net/?f=5%3C%205x%20%20%3C%2011)
Divide through by 5
![1< x](https://tex.z-dn.net/?f=1%3C%20x%3C2.2)
Substitute 2 for x
--- this is true
![(b)\ 4 < 5x - 3 < 10](https://tex.z-dn.net/?f=%28b%29%5C%204%20%3C%205x%20-%203%20%3C%2010)
Add 3 to both parts
![4 +3< 5x < 10+3](https://tex.z-dn.net/?f=4%20%2B3%3C%205x%20%20%3C%2010%2B3)
![7< 5x < 13](https://tex.z-dn.net/?f=7%3C%205x%20%20%3C%2013)
Divide by 5
![1.4< x < 2.6](https://tex.z-dn.net/?f=1.4%3C%20x%20%20%3C%202.6)
Substitute 2 for x
--- this is true
![(c)\ 4 < 5x - 7 < 10](https://tex.z-dn.net/?f=%28c%29%5C%204%20%3C%205x%20-%207%20%3C%2010)
Add 7 to both parts
![4 +7< 5x < 10+7](https://tex.z-dn.net/?f=4%20%2B7%3C%205x%20%3C%2010%2B7)
![12< 5x < 17](https://tex.z-dn.net/?f=12%3C%205x%20%3C%2017)
Divide by 5
![2.4< x < 3.4](https://tex.z-dn.net/?f=2.4%3C%20x%20%3C%203.4)
Substitute 2 for x
--- this is false because 2.4 > 2
![(d)\ 4 < 2x + 1 < 10](https://tex.z-dn.net/?f=%28d%29%5C%204%20%3C%202x%20%2B%201%20%3C%2010)
Subtract 1 from all parts
![4 - 1](https://tex.z-dn.net/?f=4%20-%201%20%3C2x%3C10-1)
![3](https://tex.z-dn.net/?f=3%20%3C2x%3C9%5C%5C)
Divide by 2
![1.5 < x < 4.5](https://tex.z-dn.net/?f=1.5%20%3C%20x%20%3C%204.5)
Substitute 2 for x
--- this is true
![(e)\ 4 < 2x + 3 < 10](https://tex.z-dn.net/?f=%28e%29%5C%204%20%3C%202x%20%2B%203%20%3C%2010)
Subtract 3 from all parts
![4 -3< 2x < 10-3](https://tex.z-dn.net/?f=4%20-3%3C%202x%20%3C%2010-3)
![1 < 2x < 7](https://tex.z-dn.net/?f=1%20%3C%202x%20%3C%207)
Divide by 2
![0.5 < x < 3.5](https://tex.z-dn.net/?f=0.5%20%3C%20x%20%3C%203.5)
Substitute 2 for x
----- this is true
![(f)\ 4 < 2x + 6 < 10](https://tex.z-dn.net/?f=%28f%29%5C%204%20%3C%202x%20%2B%206%20%3C%2010)
Subtract 6 from all parts
![4 -6< 2x< 10-6](https://tex.z-dn.net/?f=4%20-6%3C%202x%3C%2010-6)
![-2< 2x< 4](https://tex.z-dn.net/?f=-2%3C%202x%3C%204)
Divide by 2
![-1< x< 2](https://tex.z-dn.net/?f=-1%3C%20x%3C%202)
Substitute 2 for x
--- this is false because 2 = 2; not 2 < 2
Start by finding 7% of the $23.20:
![\frac{7}{100} *23.20=1.624](https://tex.z-dn.net/?f=%20%5Cfrac%7B7%7D%7B100%7D%20%2A23.20%3D1.624)
Now add this to $23.20:
![23.20+1.624=24.824](https://tex.z-dn.net/?f=23.20%2B1.624%3D24.824)
Now, let's find 18% of this new total with tax to find the tip amount:
![\frac{18}{100} *24.824=4.46832](https://tex.z-dn.net/?f=%20%5Cfrac%7B18%7D%7B100%7D%20%2A24.824%3D4.46832)
This is the tip amount. And finally, let's add this to the 24.824:
![24.824+4.46832=29.29232](https://tex.z-dn.net/?f=24.824%2B4.46832%3D29.29232)
Not sure if you were given any instructions about rounding, but Ana's cost will be around $29.29.
Hope this helps.
12/66--->x/22
12/66--->4/22 (almost 4/20 if you know what I mean)