Final answer:
The function f(x)=x² is known as a quadratic function or a second-order polynomial due to the x² term, which is the highest degree term in the equation.
Step-by-step explanation:
The function f(x)=x² is a quadratic function. This type of function is also referred to as a second-order polynomial. In a quadratic function, the highest degree of the variable is 2, which is the case with the x² term here.
Solution of quadratic equations often involves finding the values of x that make the function equal to zero (the x-intercepts or roots). Quadratic functions are known for their distinctive U-shaped curve called a parabola, which opens upwards if the coefficient of the x² term is positive, as it is in this function.