Answer:
and 
Step-by-step explanation:
First, we are told "sum of 5 times one number, x, and 4 times a second number, y, is 75":
(1)
Then, we are told "he sum of the two numbers is 18":
(2)
At this point we have our system of equations and now we are able to find the values of
and
.
So, let's begin by isolating
from (2):
(3)
Substituting (3) in (1):
(4)
Finding
:
(5) This is the value of 
Substituting (5) in (1):
(6)
Finding
:
(7)
(8) This is the value of 
Answer:

Step-by-step explanation:
We first need to know the square root of I then add 10 on that square root since r is 10 more than the square root of I
Therefore,

Answer:
3
Step-by-step explanation:
To solve this, we are going to use the surface are of a sphere formula:

where

is the surface area of the sphere

is the radius of the sphere
We know for our problem that

and

, so lets replace those vales in our formula:



Now, we just need to solve our equation for

:





or

Since the radius of a sphere cannot be a negative number,

.
We can conclude that the radius of a sphere with surface area <span>2,122.64 </span>

is
13 in.