Question

which is a quadratic function?
$f(x)=0x^2 - 4x + 7$
$f(x)=2x + x + 3$
$f(x)=3x^3 + 2x + 2$
$f(x)=5x^2 - 4x + 5$

Explanation:

Step1: Recall quadratic function definition

A quadratic function has the form $f(x)=ax^2+bx+c$ where $a
eq0$, degree 2.

Step2: Analyze each option

1. $f(x)=0x^2-4x+7$ simplifies to $f(x)=-4x+7$, $a=0$, linear.
2. $f(x)=2x+x+3$ simplifies to $f(x)=3x+3$, linear.
3. $f(x)=3x^3+2x+2$, highest degree 3, cubic.
4. $f(x)=5x^2-4x+5$, $a=5

eq0$, degree 2.

Answer:

$f(x)=5x^2-4x+5$