Question

X2-x-9<0 помогите там x в квадрате

Answer 1

x^2-x-9<0
D=b^2-4ac
D=1-(-9*4)=1+36=√37
x=-b-√D/2a
x1=1-√37/2
x2=1+√37/2
x∈(1-√37/2;1+√37/2)