Rises on the left and right

Rises on left, falls on right

Falls on the left, rises on the right

Falls on the left and right

Even

Odd

$12v+18$

$15v^2+8v$

$12v^2+18v$

$12v^2+18v^2$

$12n+2$

$12n^2+12n+2$

$12n^2+2$

$12n^2+14n+2$

 $x^2+100$  

 $x^2-100$  

 $x^2+20x-100$  

 $x^2-20x+100$  

 $5x^3-17x^2+24x+12$  

  $5x^3+17x^2-24x+12$  

 $5x^3-13x^2+24x+12$  

 $5x^3+13x^2-24x-12$