The answer is C.
You can get answers to any quadratic function by first making sure that the equation is equal to 0. In this case it already is, so you don't need to do any work there.
Next you can get the a, b and c values for the quadratic equation by looking at the coefficients of every term.
a = 4 (number attached to x^2)
b = -6 (number attached to x)
c = 1 (number with no variable attached)
Now we can use these in the quadratic equation.
[tex] \frac{-b +/- \sqrt{ b^{2} - 4ac } }{2a} [/tex]
[tex] \frac{6 +/- \sqrt{ -6^{2} - 4(4)(1) } }{2(4)} [/tex]
[tex] \frac{6 +/- \sqrt{ 20 } }{8} [/tex]