Question

Which is a quadratic function?

Answer 1

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

Step-by-step explanation:

A quadratic function is as following; $ax^2+bx+c$

Notice that it cannot be $f(x)=0x^2-4x+7$ because if you solve; $0x^2=0$ which eliminates the $x^2$.