The difference is that evaluating an expression for a given value is an example of let’s say In a example, the variable x is equal to 6 since 6 + 6 = 12. So it means that they are giving you the input already. SOLVING an equation is working backwards, to undo everything that has been done to the input. So you have to do the equation in order to find your answer.
Actually Welcome to the Concept of the circles.
It's is universally proven that ratio of circumference and diameter is always π
hence the decimal value is π = 3.14
===> answer is option B.) 3.14
The picture is incomplete and the width is missing.
I am going to show you how to do it using any width.
The length shown is x + 4 and the width starts with - x.
Assume the width is - x + a.
Then the area of the rectangle with dimensions x + 4 and - x + a is calculated in this way:
1) given: (x + 4) (- x + a)
2) use distribuitive property: (x)(-x) + (x)(a) + (4)(-x) + (4)(a)
= - x^2 +ax -4x + 4a
3) Combine like terms: - x^2 + (a -4)x + 4a
If the polynomial missing were - x + 7, the answer would be:
- x^2 + (7 -4)x + 4(7) = - x^2 + 3x + 28
With this you are able to get the answer using the real values.
Answer: dr/dt = 9/(24pi) cm per minute
9/(24pi) is approximately equal to 0.119366
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Work Shown:
Given info
dS/dt = 18 cm^2/min is the rate of change of the surface area
r = 6 cm is the radius, from the fact that the diameter is 12 cm
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Use the surface area equation given, apply the derivative, plug in the given values and then isolate dr/dt which represents the rate of change for the radius
S = 4*pi*r^2
dS/dt = 2*4*pi*r*dr/dt
dS/dt = 8*pi*r*dr/dt
18 = 8*pi*6*dr/dt
18 = 48*pi*dr/dt
48pi*dr/dt = 18
dr/dt = 18/(48pi)
dr/dt = (9*2)/(24*2pi)
dr/dt = 9/(24pi)
The units are cm per minute, which can be written as cm/min.
