Ridici ecuatia 2 la patrat
(4x²+9y²)+12xy=400=>
1)(2x+3y)²=400=> 2x+3y=20 relatia 1
2) 256+12xy=400=>
12xy=144
xy=12=>
ridici2x-3y la patrat
4x²+9y²-12xy=256-144=112
(2x-3y)²=112
2x-3y=√112=4*√7 relatia 2
Din relatia 1 si 2 faci sistem
{2x+3y=20
{2x-3y=4√7=> x=5+√7
y=(10-2√7)/3
