Х^2-5х=14
Х^2-5х-14=0
D=b^2-4ac
D=25+56=81
√81=9
<span>Х1=(-b+ √D):2а</span>
<span>Х2=(-b-√D):2а</span>
Х1=(5+9):2=7
Х2=(5-9):2=-2