use the quadratic equation in the form
[tex]x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}[/tex]write the equation in the form
[tex]ax^2+bx-c=0[/tex][tex]4x^2+9x+4=0[/tex]replace in the quadratic equation
[tex]\frac{-9\pm\sqrt[]{9^2-4\cdot4\cdot4}}{2\cdot4}[/tex]simplify
[tex]\frac{-9\pm\sqrt[]{17}}{8}[/tex]