Х^2-4х-5=0 х^2+7х+12=0 х^2-11х+10=0 2х^2-3х+1=0

1)x²-4x-5=0
x1+x2=4 U x1*x2=-5
x1=-1 U x2=5
2)x²+7x+12=0
x1+x2=-7 U x1*x2=12
x1=-4 U x2=-3
3)x²-11x+10=0
x1+x2=11 U x1*x2=10
x1=1 U x1*x2=10
4)2x²-3x+1=0
D=9-8=1
x1=(3-1)/4=0,5 U x2=(3+1)/4=1