[latex]2x^2-x-3=0\ delta=b^2-4ac=1+24=25\ sqrt{delta} =5\ x_{1}= frac{-b-sqrt{delta}}{2a} = frac{1-5}{4}=-1\x_2 = frac{-b+sqrt{delta}}{2a} = frac{1+5}{4}=1,5 \[/latex] Odp: B [latex]2x^2-9+9=0\ delta=b^2-4ac=81-72=9\ sqrt{delta} =3\ x_{1}= frac{-b-sqrt{delta}}{2a} = frac{9-5}{4}=1,5\x_2 = frac{-b+sqrt{delta}}{2a} = frac{9+3}{4}=3 \[/latex] Odp: D [latex]2x^2+9+9=0\ delta=b^2-4ac=81-72=9\ sqrt{delta} =3\ x_{1}= frac{-b-sqrt{delta}}{2a} = frac{-9-3}{4}=-3\x_2 = frac{-b+sqrt{delta}}{2a} = frac{-9+3}{4}=-1,5 \[/latex] Odp: A
