A)Х²-15х+56=(x-7)(x-8)
а=1
b=-15
c=56
D=b²-4ac
D=225-224=1
X1=15+1/2=8
X2=15-1/2=7
Б)7х²+9х+2=(x+2/7)(x+1)
a=7
b=9
c=2
D=81-56=25
X1=-9+5/14=-4/14=-2/7
X2=-9-5/14=-1
A)Х²-15х+56=(x-7)(x-8)
а=1
b=-15
c=56
D=b²-4ac
D=225-224=1
X1=15+1/2=8
X2=15-1/2=7
Б)7х²+9х+2=(x+2/7)(x+1)
a=7
b=9
c=2
D=81-56=25
X1=-9+5/14=-4/14=-2/7
X2=-9-5/14=-1