Answer:
18 is a composite number. 18 = 1 x 18, 2 x 9, or 3 x 6. Factors of 18: 1, 2, 3, 6, 9, 18.
Prime factorization: 18 = 2 x 3 x 3, which can also be written 18 = 2 x 3²
<em>hope the answer helped:)</em>
a. The first variable is x and the second variable is y.
b. The equations are
and 
Step-by-step explanation:
Step 1:
The first step is to define the variables. The variables can be any two symbols, letters, characters, etc.
Here let the first variable be x and the let the second variable be y.
So the variables are defined as x and y.
Step 2:
The sum of the given variables is 12.
The first variable + the second variable = 12,

The difference between the two variables is 4.
The first variable - the second variable = 4.

Step 3:
If we add both the equations we get,
and 
x = 8 and y = 4.
Answer:
10.28425
Step-by-step explanation:
Are = radius squared times pie so 12*12 = 144 so 144 times pi 3.14*144 = 452.16 is your answer
A is the answer hope it helps