3x^2+5x+6/x^2+4=4x^2+5x-3/2x^2-5
6x+5x+12/x+4=8x+5x-6/2x-5
11x+12/x+4=13x-3/x-5
11x-13x+12/x+3/x= -4-5
-2x+15/x=-9
-2x/1+15/x=-9/1
-2x2+15=-9x
-2x2+9x+15=0
D=b2-4ac
81+120=201
x1=-b+√D/2a=-9+√201/2^(-2)=9+√201/4
x2=-b-√D/2a=-9-√201/2^(-2)=9-√201/4
ответ: x1=9+√201/4, x2=9-√201/4