Answer:
Equation:
or 
Solution:
Step-by-step explanation:
The formula that is used to calculate the perimeter of a square is:

Where "s" is the side lenght the square.
Knowing that Xin used 20 yards of fencing to build the walls of a square chicken coop (in which the lenght in yards of each wall is represented with "x"), you can identify that:

Then, you can susbtitute values into the formula
:
Finally, you must solve for "x" in order to find its value.
This is:

Answer:
y=3x-5
Step-by-step explanation:
First find the slope, 4+2 over 3-1, giving you the slope of three
then set up your equation, y=3x+?
I played with the y=3x - part on the website desmos graphing calculator, I first inserted the points then found the slope and then played with the equation till it went through both the points.
Answer:
$55,080
Step-by-step explanation:
Hope this helps.