here is the solution:
2x^2 - 3xy -4y^2 -5 = 0
-4y^2 -3xy + 2x^2 -5 = 0
4y^2 - 3xy - 2x^2 + 5 = 0 multiply through by -1
a = 4, b = 3x, c - (-2x^2 +5)
use quadratic equation:
y = -(-3x) +or- sqrt[9x^2 - 4*4*(-2x^2 +5)]
------------------------------------------------
2*4
y = 3x + or - sqrt [9x^2 - 26(-2x^2 +5)]
--------------------------------------------
8
y = 3x + or - sqrt[ 9x^2 +32x^2 - 80]
------------------------------------------
8
y = 3x + or - sqrt(41x^2 -80)
--------------------------------
8
thank you Ann Marie