7x^2-x-8=0 уравнение

Question

7x^2-x-8=0 уравнение

Answer 1

7x²-x-8=0
D=(-1)²-4*(-8)*7=224+1=225
x₁=(1-15)/2*7=-1
x₂=(1+15)/2*7=1 1/7

Answer 2

7x²-x-8=0
D=1+224=225
x1=(1-15)/14=-1
x2=(1+15)/14=8/7