2x + y - (x + y) = 3z - 6z
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<span>x = -3z </span>
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<span>(-3z, 9z) </span>
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<span>(x,y,z) = (-3z, 9z, z)
</span>--------------------------
<span>x = -3z, y = 9z
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There for the answer is </span><span>(-3z, 9z) </span>
I set this up as an inequality,

. If you take the cubed root of 800, you get the lower bound of the side length, which is 9.2. Then I just worked my way up until I hit the first number that put me over a volume of 800. That number is 9.29, because 9.28 cubed is 799.1 (not high enough) and 9.29 cubed is 801.8. Therefore, the bounds of the sides exist within a conjunction:

. That's the best I could come up with to help on that one. Wasn't sure if there was another method you were taught at school. I just used common sense more than any rule.
Answer:
9.5 inches
Step-by-step explanation:
The radius is 1/2 of the diameter
19/2 = 9.5 inches
Part (a)
<h3>Answer: 0.2</h3>
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Work Shown
It costs $15 to rent a bike for 3 hours. We can write the following ratio below
15 dollars : 3 hours
To represent the connection of the two concepts (dollars connecting with hours)
We want the "15 dollars" to turn into "1 dollar". This is because the phrasing "per dollar" really means "per 1 dollar".
Divide both sides of the ratio by 15 to achieve this goal.
15 dollars : 3 hours
15/15 dollars : 3/15 hours
1 dollar : 1/5 hours
1 dollar : 0.2 hours
0.2 hours : 1 dollar
So we get 0.2 hours per dollar.
As a side note, 0.2 hours = 0.2*60 = 12 minutes.
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Part (b)
<h3>Answer: 3.38</h3>
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Work Shown
27 pages : 8 minutes
27/8 pages : 8/8 minutes
3.375 pages : 1 minute
3.38 pages : 1 minute
I'm dividing both parts of the original ratio by 8 to turn "8 minutes" into "1 minute" (due to the phrasing "per minute"). Don't forget to round to 2 decimal places.