1) which is a quadratic function? f(x) = 2x x 3f(x) = 0x2 – 4x 7f(x) = 5x2 – 4x 5f(x) = 3x3 2x 2

A quadratic equation is a polynomial function in which the order or the highest degree among all the terms is 2. In this case, among the given functions, the polynomial equation would have to be c. f(x) = 5x2 - 4x + 5. There are also other euqations like trinomial equations in which the order is equal to 3.