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:
Circumference of circle = 87.92 centimeter
Step-by-step explanation:
In the given question;
Radius of circle = 14 centimeters
Value of π = 3.14
Find:
Circumference of circle
Computation:
⇒ Circumference of circle = 2πr
where r = Radius of circle
⇒ Circumference of circle = 2(3.14)(14)
⇒ Circumference of circle = (6.28)(14)
Circumference of circle = 87.92 centimeter
Question:
Yan is climbing down a ladder. Each time he descends 4 rungs on the ladder, he stopped to see how much farther he has to go. If Yan made eight stops with no extra steps, which expression best shows another way to write the product of the number of ladder rungs that Yan and climbed?
4+4+4+4
8+8+8+8
(-1)(4+4+4+4)
(-8) + (-8) + (-8) + (-8)
Answer:
Step-by-step explanation:
Given
<em></em>
<em> --- It is negative because he is climbing down</em>

Required
An expression for the number of rungs climbed
To do this, we simply multiply the number of rungs by the steps taken.


This can be rewritten as:

The product, when written as sum is:
Mixed numbers are a mix of a whole number and a fraction
a easy one is
1 and 1/4+1 and 3/4
1 and 1/2 +1 and 1/2
1 and 9/10 and 1 and 1/10
etc