Consider re-writing this formula as "A = pi*r^2." The backslash symbol "\" is unnecessary.
If A = pi*r^2, and we wish to solve for r, then divide both sides by pi:
A/pi = r^2
Taking the square root of both sides, sqrt(A/pi) = r (r must be positive in this situation).
Answer:The answer is A, 15 I believe if i did the math right.
Step-by-step explanation: First you take the equation: f(x)= 0.86x-0.09
Then you plug in x witch in this case is 18 so f(18)=0.86(18)-0.09= 15.39 So round to the nearest whole number and you get 15.
1. You have the function 
2. You know that
with
, because the division by zero is not defined. So ,
for
where
is a integer number.
3. Then, to find the domain of the function given in the problem, you must make 
Where
is odd number.
4. Therefore:

5. Finally, the domain is: 
The answer is: 
Step-by-step explanation:
the last one
x^2+2x+1 R(-5)