Question

f (x)= 1/4 x2 -3x + 9

Answer 1

$f(x)=(1/4)x^2-3x+9\\\\ \Delta=b^2-4ac\\ \Delta=(-3)^2-4\cdot(1/4)\cdot9\\ \Delta=9-9\\ \Delta=0\\\\ x= \dfrac{-b\pm \sqrt{\Delta} }{2a}= \dfrac{-(-3)\pm \sqrt{0} }{2\cdot(1/4)}= \dfrac{3\pm0}{(1/2)}= \dfrac{3}{(1/2)}=3\cdot2/1=6\\\\\\ \Large\boxed{x_1=x_2=6}$