Question

Решите квадратное уравнение. 7z^2 -z-8=0

Answer 1

D=1-4*7*(-8)=1+224=225

√D=15

z1=(1-15)/2*7=-14/14=-1

z2=(1+15)/2*7=16/14=8/7

Answer 2

a=7 b=-1 c=-8
D=b^2-4ac=(-1)^2-4*7*(-8)=1+224=225
√D= √225=15
z1=1+15/2*7=16/14=8/7
z2=1-15/2*7=-14/14=-1