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:
Step-by-step explanation:
<u>Given function:</u>
<u>Plot two points and check which graph has those:</u>
and
Points (0, 2) and (1, 6) are correct on the image 1 with blue graph
Answer:
25% is called a quarter of 900
Step-by-step explanation:

Answer:61
Step-by-step explanation:
Z+Z-11=Z+50
2Z-11=Z+50
Collect like terms
2Z-Z=11+50
Z=61
3^2 = 9
9/9 = 1
1 + 12 = 13
This is based on the Order of Operations.
Hope it helps! :D