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:


Use the Pythagorean Theorem to solve for the third side. The third side must be the hypotenuse since the height (vertical leg) is 9, and the length (horizontal leg) is 5.
a² + b² = c², where a and b are the legs and c is the hypotenuse. Plug in 5 and 9 for a and b; solve for c.
5² + 9² = c² ⇒ 25 + 81 = c²
106 = c²
Square root both sides.
c = 10.3
Third side: 10.3
4/7m = 2/7(2m + 1)
4/7m = 4/7m + 2/7
4/7m - 4/7m = 2/7
0 = 2/7 (incorrect)
no solution
5/8 = 3/4+1/16 is false because, the final values compared on each side of equation is not the same
- 5/8 = 0.625
- 3/4+1/16 = 0.8125
0.625 = 0.8125, it is not equal but less than