2х + 3 = 3х+1
х-1 х+1 х ^2 -1
2x(x+1)+3(x-1)=3x+1
2x^2+2x+3x-3-3x-1=0
2x^2+2x-4=0
x^2+x-2=0
x1=-2, x2=1
2x^2+2x-4=0 :2
D=1-4*1*(-2)=9=3^2
x1=-1+3/2=1 x2=-1-3/2=-2