Solve 2x2 + x − 4 = 0 using completing the square

[latex]2x^2+x-4=0[/latex] [latex]x^2+\dfrac12x-2=0[/latex] [latex]x^2+\dfrac12x+\dfrac1{16}-\dfrac{33}{16}=0[/latex] [latex]\left(x+\dfrac14\right)^2=\dfrac{33}{16}[/latex] [latex]x+\dfrac14=\pm\dfrac{\sqrt{33}}4[/latex] [latex]x=\dfrac{-1\pm\sqrt{33}}4[/latex]