A quadratic function<span> is one of the form f(x) = ax</span>2<span> + bx + c, where a, b, and c are numbers with a not equal to zero. Therefore, options A and C are quadratic equations, </span>y=2(x-3x^2+1) and <span> y=1/2x^2-13x+4. Hope this answers the question. Have a nice day.</span>