Answer: x=8 and y=±3
Step-by-step explanation:
Perimeter= Sum of length of sides
Let A= (4,0)
B= (8,0)
C= (x,y)
So
AB+BC+CA = 12
[tex]\sqrt{(8-4)^{2} -(0-0)^{2} } + \sqrt{(x-8)^{2}+(y-0)^{2} } + \sqrt{(4-x)^2+(0-y)^{2} }[/tex]= 12
Solving it, the possible outcomes comes out to be
x= 4, y=±3
x=8, y=±3
x=2, y=0
x=10, y=0
For the largest area, we would use
x=8 and y=±3