Math.
solving quadratic equation by completing the square
help me pls.solve 2x2-3x-11=0


Sagot :

[tex]2x^ 2-3x-11=0\\\\a=2,\ \ b=-3, \ \ c=-11\\\\x_{1}=\frac{-b-\sqrt{b^2-4ac}}{2a}=\frac{3-\sqrt{(-3)^2-4*2*(-11)}}{2*2}=\frac{3-\sqrt{9+88}}{2*2}=\\\\=\frac{3-\sqrt{9+88}}{2*2}=\frac{3-\sqrt{97}}{4}[/tex]

[tex]x_{2}=\frac{-b+\sqrt{b^2-4ac}}{2a}=\frac{3+\sqrt{(-3)^2-4*2*(-11)}}{2*2}=\frac{3+\sqrt{9+88}}{2*2}=\\\\=\frac{3+\sqrt{9+88}}{2*2}=\frac{3+\sqrt{97}}{4}[/tex]