13 x 85 = 1105
78 + 91 = 169
169 / 1105 = 6.5
Answer:
2.29 ft of side length and 1.14 height
Step-by-step explanation:
a) Volume V = x2h, where x is side of square base and h is hite.
Then surface area S = x2 + 4xh because box is open.
b) From V = x2h = 6 we have h = 6/x2.
Substitude in formula for surface area: S = x2 + 4x·6/x2, S = x2 + 24/x.
We get S as function of one variable x. To get minimum we have to find derivative S' = 2x - 24/x2 = 0, from here 2x3 - 24 = 0, x3 = 12, x = (12)1/3 ≅ 2.29 ft.
Then h = 6/(12)2/3 = (12)1/3/2 ≅ 1.14 ft.
To prove that we have minimum let get second derivative: S'' = 2 + 48/x3, S''(121/3) = 2 + 48/12 = 6 > 0.
And because by second derivative test we have minimum: Smin = (12)2/3 + 4(12)1/3(12)1/3/2 = 3(12)2/3 ≅ 15.72 ft2
62,900
21,000
126,300
856,700
Follow these steps:
-8.4b - 4.2 = 12.6
Add 4.2 on both sides:
-8.4b = 16.8
Divide by -8.4 on both sides to give you the final answer of:
b = -2
So you're answer is indeed correct! Hope this helps and that the steps are clear enough!
Answer:
1150$
Step-by-step explanation:
2800$-500$=2300$÷2=1150$
hope this helped ; )
