Answer: 
Step-by-step explanation:
1. You know that:
- The roped-off area whose width is represented with <em>x,</em> it is created around a rectangular museum.
- The dimensions of the rectangular museum are: 30 ft by 10 ft.
- The combined area of the display and the roped-off area is 800 ft².
2. The area of the rectangular museum can be calculated with:

Where
is the lenght and
is the width.
You have that the lenght and the width in feet are:

3. Let's call
the width of the roped-off area. Then, the combined area is:

Where



4. Substitute values and simplify. Then:


Answer:
one
Step-by-step explanation:
they meet at only one point, thus their system of equations has as solution only those coordinates.
Answer:
Volume: 
Ratio: 
Step-by-step explanation:
First of all, we need to find the volume of the hemispherical tank.
The volume of a sphere is given by:

where
r is the radius of the sphere
V is the volume
Here, we have a hemispherical tank: a hemisphere is exactly a sphere cut in a half, so its volume is half that of the sphere:

Now we want to find the ratio between the volume of the hemisphere and its surface area.
The surface area of a sphere is

For a hemisphere, the area of the curved part of the surface is therefore half of this value, so
. Moreover, we have to add the surface of the base, which is
. So the total surface area of the hemispherical tank is

Therefore, the ratio betwen the volume and the surface area of the hemisphere is

Answer:
Step-by-step explanation:
5(2x+3) = 85
10x + 15 = 85
x = (85 - 15)/10
x = 7