0} \atop {a}\neq0 } \right. \\ \\ \left \{ {(3-a)(3+a)>0} \atop {a}\neq0 } \right. \\ \\\left \{ {(a-3)(3+a)<0} \atop {a} \neq0 } \right.\\ \\ \left \{ {a\in(-3;3)} \atop {a}\neq0 } \right. \\ \\ otvet:a\in(-3;0)U(0;3)" alt="ax^2-6x+a=0\\ \\ D=b^2-4ac\\ \\ D=36-4a^2=9-a^2=(3-a)(3+a)\\ \\ \left \{ {{D>0} \atop {a}\neq0 } \right. \\ \\ \left \{ {(3-a)(3+a)>0} \atop {a}\neq0 } \right. \\ \\\left \{ {(a-3)(3+a)<0} \atop {a} \neq0 } \right.\\ \\ \left \{ {a\in(-3;3)} \atop {a}\neq0 } \right. \\ \\ otvet:a\in(-3;0)U(0;3)" align="absmiddle" class="latex-formula">