6x² - 4x+5=0
a=6
b=-4
c=5
Δ=b^2-4ac
Δ=(-4)^2-4*6*5
Δ=16-120
Δ=-104⇒[tex] x_{1,2} [/tex]∉R
7x²-9x+2=0
a=7
b=-9
c=2
Δ=b^2-4ac
Δ=81-56
Δ=25
[tex] x_{1,2} = \frac{-b +-\sqrt{delta} }{2a} \\ \\ x_{1,2} = \frac{9 +-5 }{14} \\ \\ x_{1} = \frac{9+5}{14} \\ \\ x_{1} = \frac{14}{14} \\ \\ x_{1}=1 \\ \\ x_{2} = \frac{9-5}{14} \\ \\ x_{2} = \frac{4}{14} \\ \\ x_{2} = \frac{2}{7}[/tex]
