2x
2
−3xy−19y
2
=25
x
2
−6y
2
=250
x
2
=250+6y
2
2(250+6y
2
)−3
250+6y
2
y−19y
2
=25
7y
2
+3
250+6y
2
y=475
(3
250y
2
+6y
4
)
2
=(475−7y
2
)
2
9(250y
2
+6y
4
)=49y
4
−6650y
2
+225625
2250y
2
+54y
4
=49y
4
−6650y
2
+225625
5y
4
+8900y
2
−225625=0
y
4
+1780y
2
−45125=0
y=5
y=−5
x=20
x=−20
