(2z-7z+3)/(2z+1)-1+z=0
(3-5z)/(2z+1)-1+z=0 z≠-0,5 3-5z-2z-1+2z²+z=0 2z²-6z+2=0 z²-3z+1=0 D=9-4=5 z1=(3-√5)/2 z2=(3+√5)/2