This should be recognized as the difference of perfect squares which is of the form:
(a^2-b^2) and the difference of squares always factors to:
(a-b)(a+b) in this case:
(3x-8)(3x+8)
The answer id 12 meters.divide -2x^2+20x+48 by 2 to get x alone and then umbrella
Answer:
Length = 17 cm
Width = 8 cm
Step-by-step explanation:
Let the length be x cm
Therefore, Width = (x - 9) cm
Perimeter of rectangle = 2(l +w)
50 = 2[x + (x - 9)]
50/2 = 2x - 9
25 = 2x - 9
25+ 9 = 2x
2x = 34
x = 34/2
x = 17 cm
x - 9 = 17 - 9 = 8 cm
Therefore,
Length = 17 cm
Width = 8 cm
Thus, the dimensions of the rectangle are 17 cm and 8 cm.
Consider expression 
1. Use property

Then

2. Use property

Then

3. Use property

Then

4. Use property

Then

Answer: correct option is B.