Which equation represents quadratic time : <p><a href="https://i.stack.imgur.com/9ioTI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9ioTI.png" alt="enter image description here"></a></p>

<p>I believe it is 3n+5n^2+1 but I am not 100 percent sure. If I am wrong can someone explain to me why?</p>
