Answer: x=-2
Y= -20
Step-by-step explanation
You replace the y in the second equation with 10x. This is because it says 10x=y
2x+10x=12x so you put that
12x=-24
To get x by its self you divide by 12.
-24 divided by 12 is -2.
Now you plug in -2 to either equation as y. I chose the first one because it's easier.
10(-2)=y
-20=y
The garden area is maximum when the enclosure is a square.
If a is the length of the side of the square then the length of the building is also a.
The perimeter length is 4a made up of 81+a feet, so 81+a=4a and 3a=81 making a=27 feet.
I think it could be x=-5 and/or x=5
Hoped I help :)