Answer:
length = 22
width = 13
Step-by-step explanation:
Perimeter of a rectangle is given by the formula
P =2(l+w)
we know the length is x
width is x-9
P =70
Substituting this into the equation
70 = 2(x+x-9)
Combining like terms
70=2(2x-9)
Distributing the 2
70 = 4x-18
Adding 18 to each side
70+18 = 4x-18+18
88 = 4x
Divide by 4
88/4 = 4x/4
22= x
we know the length is x
length = 22
width is x-9
width = 22-9= 13
Answer:
Second option is the correct answer.
Step-by-step explanation:

Answer:
C = 2πr = 16.3
2(3.14)r = 16.3
r = 16.3/6.28
r = 2.5955414
Area: A = πr2
A = 3.14(2.5955414)2
A = 21.15366242 
Step-by-step explanation:
The answer would be 21.2 
CommentI think you need brackets to clarify what you mean. I think it should be written as
10b/(2b + 8)
If that is the case the reciprocal is
(2b + 8)/10b You just turn everything up side down. There are technical ways of doing this, but the easiest way is just to do what I just did.
Put the numerator in the denominator,
Put the denominator in the numerator.
You could simplify this a bit.
2b/10b + 8/10b
which reduces further.
1/5 + 4/5b
Just to make sure you understand where that b is, I will do this in
Latex.
Alternate answerIf you do mean what your wrote then the reciprocal is 2b / 10b + 8 which is 1/5 + 8 = 8 + 0.2 = 8.2
The 8 has nothing to do with the reciprocal under these conditions.
The answerI have given you all the choices I can think of without going into decimals. If you have choices, please list them under the comments.