Найти корни: 1)x^2-7x+12 2)x^2+2x-24 3)x^2-3x-108

1. x^2-7x+12=0
D=49-4*1*12=49-48=1
x1=7+1/2=4
x2=7-1/2=3

2. x^2+2x-24=0
D=4-4*(-24)=4+96=100=10
x1=-2+10/2=4
x2=-2-12/2=-6

3. x^2-3x-108=0
D=9-4*(-108)=9+432=441=21
x1=3+21/2=12
x2=3-21/2=-9