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

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

Step-by-step explanation:

A quadratic function always has a squared symbol (represented by ^2). The first answer is a linear function, the second answer is a linear function (squaring 0 results in 0, therefore it is canceled out), the third answer has ^2 (this is correct), and the fourth answer has a ^3 (this is a cube function; not quadratic)