f(x)=-33x^2+8x+3. The zeroes are found when f(x)=0: 33x^2-8x=3; x^2-8x/33=1/11;
x^2-8x/33+16/1089=1/11+16/1089 (completing square);
(x-4/33)^2=(99+16)/1089=115/1089; x-4/33=+sqrt(115)/33=+10.2738/33 and x=0.4462 or -0.2038.
Both solutions are irrational: (4+sqrt(115))/33.