X = 3-sqrt(7) ~~ 0.354249 and Y = 3+sqrt(7) ~~ 5.64575
X = 3+sqrt(7) ~~ 5.64575 and Y = 3-sqrt(7) ~~ 0.354249
x^2y^2 + x^2 + y^2 + 2xy = 40 → x^2y^2 + (x + y)^2 = 40 (1)
xy + x + y = 8 → y( x + 1) = 8 - x → y = [ 8 - x] / [ x + 1] (2)
Put (2) into (1)
x^2 [ 8 - x]^2 / [x + 1]^2 + [ x + [8 - x] / [ x + 1] ] ^2 = 40 simplify
x^2 [ x^2 - 16x + 64] / [ x + 1]^2 + [ x (x + 1)/(x + 1) + [ 8 - x] / [x + 1] ]^2 = 40
x^2[ x^2 - 16x + 64] + [ x^2 + 8 ]^2 = 40[x + 1]^2
x^4 - 16x^3 + 64x^2 + [ x^2 + 8]^2 = 40[x + 1]^2
x^4 - 16x^3 + 64x^2 + x^4 + 16x^2 + 64 = 40[x^2 + 2x + 1]
2 x^4-16 x^3+80 x^2+64 = 40 x^2 + 80 x + 40
2x^4 - 16x^3 + 40x^2 -80x +24 = 0
x^4 - 8x^3 + 20x^2 - 40x + 12 = 0
This has no rational solutions
The real solutions are x = 3 ±√7, y = 3 -/+ √7
The non-real solutions are x = 1 ± i*√5 , y= 1 -/+ i*√5