D=b²-4ac
x1,x2=(-b+-корень изD)/2a
x² -3x +2 =0
D=9-8=1(a=1,b=-3,c=2)
x1=(3-1)/2=1
x2=(3+1)/2=2
-x² -2x +24 =0 *(-1)
x² +2x -24 =0
D=4 +96=100=10²
x1=(-2-10)/2= -6
x2=(-2+10)/2=4
x² -7x +12 =0
D=49 -48=1
x1=(7-1)/2=3
x2=(7+1)/2=4
-x² -5x +6 =0 *(-1)
x² +5x -6 =0
D=25 +24 =49 =7²
x1=(-5-7)/2= -6
x2=(-5+7)/2 =1