The given equations are,
x+y+xy=12
yx+y2+x=12x
y2+xy+x−12x=0
y2+xy+12x=0 (1)
And,
(x+y)xy=12
x2y+x=12
x2+xy−12y=0 (2)
Subtract equation (2) from equation (1),
y2−x2+12(x+y)=0
(y+x)(y−x)+12(x+y)=0
(y+x)(y−x+12)=0
x+y=0
x=−y
And,
y−x+12=0
y+y=−12
2y=−12
y=−14
x=14
Therefore, the values are x=14 and y=−14.