[tex]2x^2+x-56=0 \\\\a=2 , \ \ b=1, \ \ c=-56 \\\\x_{1}=\frac{-b-\sqrt{b^2-4ac}}{2a}=\frac{-1-\sqrt{1^2-4 \cdot 2 \cdot (-56)}}{2 \cdot 2}=\frac{-1-\sqrt{1+448}}{4} =\frac{-1-\sqrt{449}}{4} \\\\x_{2}=\frac{-b+\sqrt{b^2-4ac}}{2a}= \frac{-1+\sqrt{449}}{4} [/tex]
