Question

Which of the following is a quadratic function?

a. y = x2 – 81

b. y = x4 – 64

c. y = x – 9

d. y = x3 – 27

Answer 1

a. y = x^2 – 81 is a quadratic function.
According to the definition:
A quadratic function is defined as a function with the maximum coefficient of 2.Only first option has a coefficient of 2 and the rest have not.