2000x^2+3000x-91.8=0
x^2+1.5x-0.0459=0
(x+0.75)^2-0.5625-0.0459=0
(x+0.75)^2-(0.78)^2=0
(x+0.75+0.78)(x+0.75-0.78)=0
(x+1.53)(x-0.03)=0
x1=-1.53 x2=0.03