Х^2-36=0
х^2=36
х1=6
х2=-6
5х^2+1=0
5х^2=-1
х^2=-1/5
корней нет
0.5х^2-1=0
0.5х^2=1
х^2=1÷0.5
х^2=2
х1=-V2
x2=V2
0.6х+9х^2=0
х(0.6+9х)=0
х1=0
0.6+9х=0
9х=-0.6
х=-0.6÷9
х2=-6/10×1/9
х2=-3/5×1/9=-1/15
2х^2-5х-3=0
д=25-4×2×(-3)=49
х1=(5-7)/2×2=-1/2=-0.5
х2=(5+7)/2×2=3
3х^2-8х+5=0
д=64-4×3×5=4
х1=(8-2)/2×3=1
х2=(8+2)/2×3=5/3=1 2/3
х^2+7х+12=0
д=49-4×12=1
х1=(-7-1)/2=-4
х2=(-7+1)/2=-3
х^2-2х-35=0
д=4-4×(-35)=144
х1=(2-12)/2=-5
х2=(2+12)/2=7