645/8= 80.625 lol why do u even need this
If x represents the width of the poster (including borders), the area of the finished poster can be written as
.. a = x*(390/(x -10) +8)
.. = 8x +390 +3900/(x -10)
Then the derivative with respect to x is
.. da/dx = 8 -3900/(x -10)^2
This is zero at the minimum area, where
.. x = √(3900/8) +10 ≈ 32.08 . . . . cm
The height is then
.. 390/(x -10) +8 = 8 +2√78 ≈ 25.66 . . . . cm
The poster with the smallest area is 32.08 cm wide by 25.66 cm tall.
_____
In these "border" problems, the smallest area will have the same overall dimension ratio that the borders have. Here, the poster is 10/8 = 1.25 times as wide as it is high.
Answer:
The height of the tent = 3 feet
Step-by-step explanation:
Question
Syrus is buying a tent with the dimensions shown below. The volume inside the tent is 36 feet^3. Syrus isn't sure if the tent will be tall enough for him to sit up inside. The tent is the shape of triangular prism whose length is 6 feet and width is 4 feet. What is the height of the tent?
Given:
Length of the tent = 6 feet
Width of the tent = 4 feet
Volume of the tent = 36 
To find the height of the tent.
Solution:
Since the ten is in shape of triangular prism, so the volume of traingular prism is given as:
where 
represents length, 
represents width and 
represents height of the prism.
Plugging in the know values of the dimension of the tent and the volume to find the height of the tent.
Simplifying.
Dividing both sides by 12.
∴ 
Thus, the height of the tent = 3 feet
Answer:
(-4,2)
Step-by-step explanation:
First we have to find a common multiple to use to add and find the system of equations. We need to eliminate one of the variables in order to solve.
Since 5 * 3 = 15, and 3 * -5 = 15, -15x and 15x will cancel each other out. Therefore x will be eliminated.
Before:
5x + 2y = -16
3x + 7y = 2
After:
15x + 6y = -48 <----------Now we solve for y
-15x + -35y = -10
+----------------------
-29y = -58
-29 -29
y = 2
Now what we do is we choose and equation and solve for x, since it is still unknown. Any equation is fine but I will choose the second one since it has easy numbers.
3x + 7y = 2
3x + 7(2) = 2
3x + 14 = 2
-14 -14
----------------------
3x = -12
3 3
x = -4
Therefore our final answer is (-4,2)
