35х²+2х-1=0 a=35 , b=2 , c =-1 D=b^2 - 4ac= 2^2 - 4*35*(-1)=144 x1=-b+\sqrt{D}\2a=-2+12\70=10\70=1\7 x2=-b-\sqrt{D}\2a=-2-12\70=-14\70=-0.2