Question

Which is a quadratic function?
f(x) = 2x + x + 3
f(x) = 0x² - 4x + 7
f(x) = 5x² - 4x + 5
f(x) = 3x3 + 2x + 2

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 $x^2$.