Question

2. Which of the following represents a quadratic function? (Circle all that apply!) (2 pts)a, y = 9x2 + 4x - 6b. y = 3x + 8c. y = 1223 - 6x2 + 4x - 9

Answer 1

A quadratic function is a function in the form,

$\begin{gathered} y=ax^2+bx+c \\ \text{where a, b, c are real } \\ a\ne0 \end{gathered}$

Option A is a quadratic function,

Option B, is not a quadratic function because it is not the form of the equation written above and also,

$a=0$

Option C is also not a quadratic function because it has the highest degree of x to be 3.

In option D the function is given by the function is defined by

$\begin{gathered} y=x^2 \\ \text{thus} \\ a=1\ne0 \end{gathered}$

This implies that the function in option D is a quadratic function

Option E is not a quadratic function